This has been a great thread of posts and I have received about 30 PMs on the subject too, many offering me pistols for sale or drawing my attention to ones others are selling as well as more advice.
I haven't jumped yet!
The conclusions I have drawn so far are now based on second hand prices as well as new from your threads, PMs and follow up reading:
-Rohm - Not much positive feedback
-Air arms Alpha - not much said, other than low shot count
-FAS 6004- not as good as the FAS 604, but good looker, good trigger, self contained, light.
-FAS 604 - sweet trigger, reasonably light, maybe too barrel light, low power unless seals regularly replaced, possibility of machining valve to increase power to get 400fps. Prices vary from £170-£310.
- Gamo Compact- cheap, light, low power, similar to FAS in concept, but poor trigger needs work from the box and not in same quality league as FAS.
-Air match 400- similar in look to FAS but side lever. Lovely looker but possible issues with spares, heavy to cock.
-Tau7 - some good and some say it's bad. Can tinker with trigger but it's CO2 and for some reason, I don't fancy the caplet thing and adding £3 CO2 cost to a tin of pellets. Someone mentioned filling from a fire extinguisher.
-Smk - no open sights but great value, can try adding sights from another gun to scope rail- sounds a bit of a bodge( why didn't they include sights?!)
-Baikal 46-most seem to rate it highly, definitely front heavy and often described as slightly agricultural. New ones in short supply, second hand ones even rarer. Good value.
-Original 6g/6m/10 -good guns, heavy, expensive maintenance if not been looked after
-Fwb 65/80 - good starting gun, great trigger, some hate side lever and or don't like the twang!. High service costs if not running right. prices vary from £120 to £500 depending on collectability.
-Fwb 100/103 - great gun, very few for sale, prices upto £500(gunstar!)
-Morini 62- fab gun but generally more in the £600 price bracket with old cylinders unless it's a fixed cylinder which has its own drawbacks
-Steyr lp1 - fab gun, no negative comments, generally £500+ for a good one
-Walther- no one has mentioned them, oddly
-Hammerli- not as good as Steyr, few second hand ones around

General conclusions
-Prices vary a lot, driven by condition, originality and inclusion of original case, manual and accessories which starts to generate a collectors premium.
-Gunstar prices are often high, better checking gun shops or joining clubs
-Everyone loves some and hates others. It's a very personal thing with lots of recommendations to try before you buy
-Check charged cylinders in a bucket of water to check for leaks
-Replacement cylinders cost around £250 per pair depending on model but they can be serviced for around £35 each
-Old cylinders are meant to be replaced after 10 years, not actually found a manufacturer say this but large ISSF competitions do check. No one seems too fussed about having 20 year cylinders unless they leak. If you get to big competitions, but a new spare cylinder.
-Full gun services, especially springers, can cost £100+ to get them back to perfection
-There seems to be quite a bit of trading-up as people perfect their collections, getting a better one then getting rid of the less perfect version, with many people having quite large collections!
-Everyone has been very helpful and understanding of my dilemma

So where do I think I'm going?
Option 1 -go for a cheaper gun to get started -try a Baikal 46 for feel ( is it too front heavy for me?) or get a mid range FAS or Fwb 65/80 , spending around the £200-£300 bracket and later justify moving into the newer high end second hand guns. Must be sound and not need servicing other than perhaps seals which I could learn to do
Option 2- increase budget to £500-600 and wait for a Morini 62 or Steyr LP1 that's right- still seems a lot to pay for a 20 yr old gun! Will need to do careful stakeholder management of Mrs L to achieve this!

Did I miss anything guys? Thanks for all the input. Now, off for a chat with Mrs L......