planing our next trip (France + England)...Doable ?

Very doable! We spent just over 4 weeks in France and the UK this spring. A week in Normandy/Brittany is good with a car. You will have to return to Paris for the EuroStar to London. For natural beauty in the UK, consider Wales or the Southwest Coast. Great country and coastal walking near St. David’s in Pembrokeshire and the Brecon Beacons National Park is lovely, but you will benefit from a car in both locations.

Edinburgh is nice as well, but it is another large city. In Northern England take a look at the Lake District (car is best) and York.

We have visited France and England both on a couple of occasions. The train ride is very easy and quite fast, but I do suggest booking as far in advance as possible to get the best ticket prices.

I have no experience selecting sites that would appeal to children, however for that purpose It might be worthwhile to investigate Warwick Castle, which is a lovely spot that the Tussaud's group has ruined for adults by turning it into a theme park. https://www.theimpartialobservers.com/p46239158

I've not encountered anything in Edinburgh that I would recognize as being interesting to children, although I suppose there must be something. When visiting there we prefer to take the night train, which might be an interesting experience for children also. Sleeping in a compartment might be fun for them.

I was going to say the same thing as Emma! Visiting England is nice, and visiting Edinburgh and Glasgow is nice, but they are not the same thing.

As far as kids and Scotland , what could be more enchanting for kids than all those castles (both ruined and refined), the ties to Harry Potter (Glenfinnan Viaduct and sites at Loch Shiel, the cafe where JK Rowling did her writing in Edinburgh), Scottie dogs, trains, boats, the ocean, kilts, and the Loch Ness monster? I lived in Scotland as a child and thought it was magical. We took my nieces three years ago when they were 8 and 11, and they could not have loved it more. The tall boat behind the Transport Museum in Glasgow was also a big hit. But really what is great about Scotland is the natural beauty.

Hmm, I did not assume that the OP thought that England and Scotland were the same thing but maybe he or she did. It read to me like 2 weeks in London and some other place in England (note the period after England) or new thought and new sentence Edinburgh and Glasgow instead of some other place in England.

Yes all very doable and easy to get around! I just flew into Edinburgh, stayed there for a few days then took a train from Waverly station to London's King Cross Station. This took a little over 4 hours. Stayed in London then took the Eurostar train from St.Pancras station to Paris in about 2 hours. While staying in Paris we did a day trip to Disneyland taking the RER trains. We had a wonderful time seeing all the different places. Highly recommended!

This seems very doable because you are keeping your number of bases to a minimum and not trying to do too much. Our kids were just a few years older than yours when we spent 3 weeks in Britain: one week each based in London, Bath, and one in Stirling in Scotland. They didn't think they wanted to go--within two days they loved it.

This seems very doable! I haven’t spent a lot of time in either city with the kids, but I think having a relaxing pace and not rushing around is key.

There are lots of children’s books/chapter books to get the kids interested about the cities, too, which will help spark their interest and prolong their attention spans while there (magic tree house and flat Stanley both have books that come to mind in Paris and London). We did this before visiting Italy last summer and it was a great motivator.

If your kids are Harry Potter fans, mine (6 and 9 at the time) loved the Warner brothers Harry Potter studio tour north of London. It could take the whole day but It was a huge hit.

A few of my friends with kids were down at Puy de Fou this summer and said it was absolutely amazing!!!