Apologies in advance if this is in the wrong section. I'm looking to get a small (as in around 4.5m2) single story extension done, which will probably involve installing 2-3 RSJs as load-bearing walls will be changed. The builder who was recommended to me is pushing me to use his architect and said he would expect it would cost around ?2K including the specs from the structural engineer. Does this sound reasonable, or am I paying over the odds for not going locally?