We were planning an extention, but had some challenges around what planning permission we needed - given previous owners had already done some work... We saw RESI ran an option to speak to a planner initially for a low cost, and discovered the process was much more complex, and the risk of getting permission was quite high, which our builder and previous architect had not mentioned at all.
So we then took RESI up on their full planning support service, and feel much more informed, and have manage to derisk the plans a bit more as a result. So hopefully on our way to getting our extension sorted