Anniversary ideas?

Its our 1st Anniversary on Saturday and I am frantically trying to come up with something memorable to do and am at a total loss. I'd prefer something different than dinner and theatre, or a dinner cruise on the Thames which is what every website seems to recommend.   Any other unique suggestions?  We live in Surrey, so can easily travel to London, but can just as easily go down to the coast.   We dont have anyone to watch our dog on short notice, so we cant go away anywhere for the weekend. 

For our anniversary, we went to a nice hotel and had a champagne tea, which is just a cream tea started off with a glass of champagne.  We got dressed up and pretended we were posh, and it was great fun.  The place we went to was in Bristol and they serve a fantastic tea with scones, jam and cream of course, but also with several different kinds of sandwiches and cake and all the tea we could drink.  I'm sure there's someplace in London where you could do something similar if that takes your fancy.  I really enjoyed it because it's such a British thing that you really couldn't do in the US.  Plus I love cream teas. 

I've always wanted to do the Hampton Court Palace maze http://www.hrp.org.uk/HamptonCourtPalace/maze.aspx and then finish somewhere with

a nice hotel and had a champagne tea, which is just a cream tea started off with a glass of champagne. 

Probably not an anniversary thing, but one of my favourite memorable things I've done in London is we went to Greenwich and stood on the Greenwich mean line.  We even got the cheesy certificates to prove we had done it.  It was really fun, and since we're big into history it was fun to wander around the Royal Observatory.  It's kind of fun if you haven't done it before.

this isn't exactly what you're looking for, but if you end up doing something in london and are looking for a restaurant afterwards, i can highly recommend Hakkasan (http://hakkasan.com/) -- we went a few months back and had the most amazing dim sum and cocktails i have ever had in my life and i loved the decor and atmosphere in general...it was definitely my favorite dining experience i've had here so far.  oh and the vegetarian options we tried were fantastic, too... though a bit of warning: it was a bit hard to find and definitely required looking up a map on my phone, and it is pretty expensive.  

For our anniversary, we went to a nice hotel and had a champagne tea, which is just a cream tea started off with a glass of champagne.  We got dressed up and pretended we were posh, and it was great fun.  The place we went to was in Bristol and they serve a fantastic tea with scones, jam and cream of course, but also with several different kinds of sandwiches and cake and all the tea we could drink.  I'm sure there's someplace in London where you could do something similar if that takes your fancy.  I really enjoyed it because it's such a British thing that you really couldn't do in the US.  Plus I love cream teas. 

We did this at the Ritz in London for Valentine's day.  It was amazing!

Also http://www.rules.co.uk/ is supposed to be fun in you want to do a bit of celebrity spotting.

Thanks for the suggestions!

MLG - You should do the Hampton Court Palace Maze - I've been through a few times and its good fun!

Have you thought about something like a spa?

Or a massage workshop for two? http://www.redletterdays.co.uk/Experience/Ref/SUSMW

Sounds a bit steamy. You even get a private room to "practice".