I'd take the conservatory issue up with the complaints partner, may get you a bit off your bill to compensate for the delay and inconvenience caused. If they are unwilling to look into the issue then you could suggest that you will refer it to the Law Society Customer Complaints Service for them to advise.
As regards your lender, your solicitor should do this and mke sure they've checked everything is fine. They may just have to sign the certificate of title (which is sent to the lender when requeting mortgage funds) stating they are satisfied with the title (so the lender can go after them if there's a prolem).
They may have to report it to the lender though. You could check the CML guidelines for your lender here...
http://www.cml.org.uk/handbook/frontpage.aspx. Click on England & Wales and select your lender and check out Part 2.
As for your deposit if you are not going to use the money you could see if they could put it in their deposit account for you and account to you for any interest (check the rate) or they can send it back to your instruction.
if they say there is a fee, ask what for. If they say it's a TT fee (telegraphic transfer), usually about �30 plus VAT, state that they could send it by BACS rather than CHAPS. This takes 3 days (CHAPS is that day) but is free.
I'd state that the least they could do is to send it by CHAPS without charging you as they caused the delay.
If it's an admin fee for the work involved i would suggest the same reponse.