How many pounds and euros to bring

No need to bring from the States. Simply use an ATM to withdraw currency upon your arrival. Couldn't be easier.
However if you insist on paying a fee to get pounds and euros from a bank here and take with you then take 40 pounds and 40 euros. That will get you from the airport to your hotels and a bite to eat before you find a bank ATM to withdraw monies from.

I don't usually bring any, unless I just have some left over from a previous trip. The exchange rate in the US is terrible. You will do much better to withdraw from ATMs at your destination. We usually withdraw the maximum our bank allows at one time, and then don't have to do so many transactions. Do your research ahead of time on networks your bank or credit union participates in. There are many threads on here about notifying your bank, etc., ahead.
Happy travels.

I like landing with about a hundred dollars in local currency so that I don't have to rush around finding a working ATM. It will cost about $10 to get a hundred equivalent at your local bank or money exchange at the airport. After that I rely totally on bank owned ATMs with a debit card - cheapest and most convenient way to go.

I, too, like to have a couple hundred in local currency when I arrive so I am not dependent on the ATMs on ararival. In my case, of course, I've bought it back from my last trip, so it doesn't cost me anything except lost interest between trips.

If you don't already have it from a past trip, you can get euro or pounds from Wells Fargo online or from a branch (you didn't say where you live) for 5% (avg) over the international rate. Since people often pay 3% to 5% to get cash at an ATM, getting a little before you go is not that much extra expense.

I have gone to Europe for 13 of the last 14 years for about a month each time. I always wait until I land at my destination airport to use a debit card to get local currency from an ATM machine. I have never had to rush around to find an ATM machine that is affiliated with a bank or is in the network of my debit card. They are all over the place at any airports that I end up landing at. I have never had a problem waiting until I arrive in Europe to get local currency however I do take whatever leftover European currency I have from the year before, if any. I take two debit cards and two credit cards all from different financial institutions so that I have back-ups incase something bad happens to one of them. I make sure to notify the financial institutions whose cards I am taking of the dates and places of my travel so that they do not refuse any charges I make in Europe. Happy Travels

Your question is a FAQ. Rick Steves travel tips address your question:
https://www.ricksteves.com/travel-tips/money/cash-tips

Rick's basic answer is: "Don’t buy foreign currency in advance. Some tourists just have to have euros or pounds in their pockets when they step off the airplane, but smart travelers don’t bother and know better than to get lousy stateside exchange rates. Wait until you arrive at your destination; I’ve never been to an airport in Europe that didn’t have plenty of ATMs.

Rick (and my answer) is 0 GBP and 0 EUR needed from the States. That said, some folks feel more comfortable having destination currency in their pockets on arrival and don't mind the cost and effort in getting the foreign exchange while still at home. If you fall in the later category, bring the minimum for the first country you and some amount to cover nominal transportation from the airport and a meal or two should certainly be adequate while you locate an ATM cash machine. If you are really paranoid about an ATM failure, bring cash to cover two or three days of cash needs.

I have ATM cards from two different financial institutions and two credit cards, all of which I notify the bank/credit unions of foreign travel planned and have their call from foreign country telephone number.

I do confess to not re-exchanging left over currency from earlier trips and have a collection of CAD, EUR, GBP, NOK. But on my first trip to Copenhagen this winter, I arrived with zero DKK and the airport ATM spit out three crisp 500 DKK notes. As it turned out, Denmark is pretty modern and credit card usage is not discouraged even for relatively small purchases. I had to make a point on spending my 1500 DKK.

PS While not applicable to your stated travel plan, I'm wondering what those who feel the need to arrive with local currency do for an Easter Europe tour. Do they buy Croatioan Kuna, Hungarian Forint, Czech Kurna in addition to Euros from their local Wells Fargo Bank?

jg I will repeat what most of the others have said, get money over there. I did a little online research and saw the numerous locations of ATM machines in Scotland for my bank/debit card. I scoped out an ATM that was about 20 miles from the airport on the route we were taking as we drove to Ft. William. I went to google earth, located the little town, and hit the "street level" icon and was able to see exactly where the ATM was located and a handy spot to prk just around the corner! Piece of cake, I also signed up for a Charles Schwab checking accout with a debit card so there were no foreign transactions fees and the checking account is no fee. On a recent trip to Italy I was a bit more concerned about the ATM locations so I checked out the Pisa airport website and learned where the ATM was located and made my first withdrawl from there, no line, no problem. So, I would get my cash over there. Also at the end of my trip in Scotland I had a few pounds left over so I asked the B&B if they would take part payment in cash and part on my card, no problem, if you have cash at the end this is good way to empty your pockets for the trip home!