A little warning about London -

When I was there last you needed a membership for each of the casinos you wanted to enter. The member ship was usually free (there are exceptions) but required 24 hours to complete your membership request.

That said, you can apply for most of them (such as casinos owned by Gala, Grosvenor, Stanley, and Hard Rock) online prior to leaving. You also need to check the dress code for each individual casino. Most were pretty reasonable (comfortable clothes are fine, no tennis shoes).

Heres a starting point for Grosvenor (http://www.grosvenor-casinos.co.uk/static/MembershipForm.htm)

I'll bet Dublin will have the same rules, but someone else can chime in on that.

Amsterdam is rather a nice casino. Its next to the Hard Rock Cafe in a nice section of town. It does have a small entry fee. Dont forget all the nice 10euro chips on the roulette tables. And last time I was there they were teaching Holdem (in Dutch) but were using NV chips that somehow ended up in my pocket.