For a Desmoquattro you'll want 'bent' ones - fold the end so that you have about 20mm sticking out at around 45 degrees to make it easier to get in the limited space. Can't recommend a specific brand, would think any decent set with a good range would do. Halfords probably as good as any...
I use an angled set bought from FROST CAR RESTORERS. I've found their website and it look like they're £14 now. Ideal for Desmoquatros, but they do straight ones too, but as said Halfords might be cheaper.
have bought these before (150 mm blade) :- http://www.ebay.co.uk/itm/DRAPER-52339-DUAL-READING-LONG-BLADE-COMBINATION-FEELER-GAUGE-/271070267398 You can then carefully bend them to suit which are better than some that come with a pronounced bend in them already as you end up partly straightening these anyway.
Chris, those are perfect, many thanks, i just ordered some. 20yrs i've made do with a set of shite ones!
Well to be fair, you've only got yourself to blame for putting up with them. However on. Positive side, thank god for the Internet and orums, otherwise you'd be stuck with your old pair for ever.