Definitely worth trying Seamus Dillon at Clover Barn. I also bought a lovely Irish cross from him last year and he is exactly as Seamus described. Seamus was a great horseman - a very quiet rider. He let me try a few horses and didn't try to hassle me into a purchase and was also happy to enter into negotiations! I took my rider instructor who agreed that all his horses were lovely. He also had some very unusual colours and markings if you want something different.
Good luck - I'm still looking for something similar to what you are and our budget is £3k and I still haven't found anything suitable :-( very despondent now - you may well be lucky though, it can depend on your area. We are in Suffolk/East Anglia and nothing much about :-(