Cellar Conversion Quote

Joellypops

Hoping someone might be able to help with my nerves!
We live in a listed end Victorian terrace that currently has a large cellar that mirrors the layout of the floor above, about 65m2 in total (4 rooms and a corridor). It has high ceilings already (no need to dig down) and 4 boarded up windows so plenty of natural light and a large open fire place for some ventilation. It's definitely not the dampest cellar I've been in but is damp as it's a cellar, it's not habitable (but it does not flood and no issues with water table in the area). We're looking to have it made habitable (used for storage, office, lounge) and trying to find someone to take the project on and basically do it all, we've had a quote so far that covers:

• Damp proofing membranes, pumps and alarms etc,
• New doors & wooden windows made to conservation spec, fire escape grilles at street level,
• Plastering,
• Lighting and plug points etc,
• Radiators installed throughout,
• Insulation between cellar and floor above, 
• Bathroom W/C with toilet and water basin,
• 30 Year guarantee on the damp proofing,
• 10 Year guarantee on their work and fit and finish,
• All management of it taken care of, along with planning consent etc

Basically everything taken care of and we're left to decorate! I've really struggled to get quotes as it seems contractors in the area don't want to take all the work on (most won't handle the full project), or too busy to take on new work. I've had one quote from a local company that has done a bunch of similar conversions on neighbouring streets and has a great reputation (work looks excellent quality, not a bad word said about them), they've quoted for the above about £39K inc VAT. I'm just wondering if anyone has had all in cellar conversion work before and if the quote sounds reasonable? I'm really struggling to get any other figures to compare against. Thanks, really appreciate any input.