I bought a Ribble Sportive from Ribble on the Cycle Scheme last year. Ordered it in July 09 & at the time of ordering, asked if it was in stock as I needed it for a trip to the Alps in August – was told yes. I received the bike in September 09 after considerable chasing.
I was measured on a jig in the Ribble shop and advised that a small (49) frame would suit me (I am 5'8''). I wasn't sure and they did not have one I could test but I went with their advice. The frame was too small (top tube too short) so I sold it on here in May and transferred all the components onto a Litespeed frame (also bought off here).
The frame itself was great & the quality was brill for £1k. I will not buy from Ribble again however.
My advice would be to make sure that Ribble have stock before ordering. If you can, get it in writing and get some commitment from them.