travelling to Europe how much money do I need to take with me.

Well doesn't Cosmos suggest an amount? I do know tours like that tend to offer alot of extra tours etc.. at extra cost too!
I think tours like that also provide all your breakfasts too right? So you need about 20 dinners and 31 lunches . Is tour just in Great Britian, or all over Europe?

I think , since hotel is all paid for, I could spend about 50 euros a day per person for food( I don't eat fancy).

I have no idea about tips, I know they expect tips on that tour,, the guide and driver anyways. MOst places you eat in Europe do not expect much in the way of tips , if at all... but , they are also private tour guides your tour may use, that may expect a tip too, I am not sure about that though.

Spending money is your choice. I rarely waste much on shopping,, but , you could also look up the sights you plan on visiting on your two extra days on your own and see what the admission is,, thats easy enough to do, almost everywhere has a website.

The cost per person is really within a broad range. If you skimp on lunches and buy sandwiches, drinks, etc. you can get by on 20 Euros for both of you. However, if you choose to site down for each dinner it will cost you 20 Euros each. You can also pick up picnic foods at grocery stores, etc. Decide before hand what your budget is and then decide how to fit your eating into your budget. Your tour company can help you with the extra tours. If there is little free time, there will be no need. Cosmos offers optional excursions and will assist you with other potential tours. Given that you are taking one of their longest tours, I am sure they would be willing to assist you. Get a few travel books to familiarize yourself with the countries and they will also be sources of things to see and do. Cheers.