Rose bike

[Andy-56]

Same here Huw, I'm 5ft 9 1/2 with 83 inseam and they recommended 53cm frame.
It'll be here in 2 weeks...touch wood

 

[Kbrook]

I have a Rose pro SL 3000. I am a 59 on the Rose and every other bike a 58. In my opinion if your 54 Trek fits you well a 51 Rose will be too small.
It's free to return a bike by the way if you have to, I've done it. Last point it's a brilliant bike you will love it.