Thanks for the call, Baz. I'm sorry I wasn't on when you posted it.
Well it looks like you've found the right people for the job. That's very detailed, and obviously from someone who knows what's entailed.
On the face of it, that's a very professional quote. Obviously a lot of thought has gone into it.
The pricing is not too low, which might arouse suspicion. I think that pricing is spot on.
Be aware though, that anything involving Planning is never as simple as the "length of a piece of string." It would be quite normal for variations to crop up during the process. I wouldn't expect anything onerous though. It is, after all, a simple routine process.
I don't know whether it does involve building over, or within 3m of, a drain/sewer. If it does, then a chat with Severn Trent at this stage would be well worth the effort.
Building over drains is usually possible, but likely costs need to be factored in.
Good quote. I would certainly go for it.
Good luck to you :o)