Okay I found my transaction by pasting my address into the block explorer url rather than searching .... my transaction is there, first seen in block 186079.
My client currently says downloaded 174981 of 186196, but it's not moving very fast. When it gets to 186079 I get my BTC, I guess?
Apologies for my stupidity if this is the case, but why so slow?? Should I have donated more?
Your bitcoins are safely at your address.
The only issue is that your bitcoin client hasn't downloaded block 186079 yet, so it unable to see them.
Once you've downloaded every block, keep your client running you will see transactions instantly.