What size would you recommend for someone 5ft 10/178cm?
A medium is probably what you need, I am 6'3" and ride a large.
Is there any leeway? The reason I ask is that I have been offered a very good deal on a SH large one. I understand they come up quite short?
5ft 9 and on a medium, not sure I'd want to stretch to a large although not actually tried one.
I'm 5ft 11 and ride a medium. Fits me great.
If you're herts & bucks based ever you're welcome to have a sit on mine.
Thanks for the offer, but this has pretty much confirmed what I thought; that the large I have been offered is too big.
I'm a mere 5' 8" and I've ridden around on a large and it was only a smidgen too big for me. They have a super steep seat angle, so it feels like a short top tube when you are sitting down, but as soon as you get your weight back it feels like a completely different bike.
I reckon with an inline post and a 50mm stem you could get away with it, but bike fit is obviously a very personal thing, so ymmv.
Wow!! I've just learnt some new internet slang. Awesome 
Good to know, thanks for your thoughts 'hat.