OK I said I'd report back so here goes...
Unfortunately I didn't get any incredible information that would answer all my prayers in terms of running a successful Adwords account. No silver bullet, fantastic short cuts, tricks or revalations that will turn it around overnight.
I did however get a lot out of it plus it was great to meet my Google rep & others face to face. For what it's worth here's what I learnt (and it's all public info anyway....)
1) You would get fat working there. Free lunches, brekky, snacks & drinks all day long. Plus the standard pool tables, table tennis, WII, massage chairs etc
2) Landing Page has no effect on Adwords Ad rankings! This one blew me away & will save me hours of tweaking landing pages to improve rank. You probably all knew this already but it was new to me. Landing pages only matter to getting you in the listings at all. Basically if you show up, even in posistion 15, the landing page has done its job & best to concentrate on other stuff.
3)use www.google.com/adpreview to test ad serving so as not to pollute your own stats
4)CTR is by far and away the biggest factor for QS (and is normalised - ie the CTR of each KW is compared against the average CTR for that particular position in that particular search)
5)setting up targetted content only campaigns can be very effective (eg targetting related industries. With clever KW you can make your ad for mattresses appear on a site for bad backs)
6)Having 75,000 KW in my account is probably not the best idea!
7)Match type does not influence ad rank
8)Google reps don't know (or aren't saying) what the non-public factors for QS really are
9)Ideal adgroups should probably only have about 25 KW in
10)The engineers really do talk about the Simpsons etc...
Hope this helped someone!