Well quite a bit really.
Unlike many others on the net in the last few days I'm not going to regale you with all the deep conversations I had with Iain, and there's good reason for that... there weren't any. Sure I espied him from time to time at some of the finescale type shows, but that was it. The influence (and it is a huge influence) was via the writing...plus one.
This one was at the much missed Heathfield shows. Not being brought up with the Constructor I didn't know who he was, but he was billed to give a talk with Bob Barlow (also not known) on light railways. I'm not usually drawn to talks. However this one I sat through and was completely inspired and fascinated. I was one above track mat level at that point, and in 40 minutes it changed everything. Seriously everything. I bought books, found these magical light railways, discovered narrow gauge and started modelling in 009.
I bought the 1990s layout design book, swallowed it virtually wholesale, and was still using the Ullysses design of board support up to Wood End in the early 2000s. Then there were the wagon books: both RTR and kit built. Sensible pragmatic advice on how to improve things. Then MORRIL which was a bit hit and miss, but with Rice-ian writing that engaged and drew you in.
Would I have ever been the modeller that I am? Without Iain Rice? Completely and categorically no.