40 Sqm extension with internal alterations quote - is this reasonable ?

[Midlands]

I have been quoted 140K (Vat Inc) for a skim finish shell with electrics/plumbing/windows/kitchen/bathroom/external render not included. It is an Edwardian house with 3m ceiling height in the Midlands. It will add/replace 40 Sqm . Really difficult to even get someone to come out and quote (perhaps becauuse the house is so old?) , just wanted an opinion of whether this is the current market rate or is this too much. The builder does have good reviews from work colleagues that have used him so happy to pay a bit extra for that piece of mind.

I don't know because we haven't had a full quote yet, but a builder we have used before said around £40-£50k for a 30 sqm extension. That doesn't include glass, kitchen, electrics etc. The loft conversion was looking more like £65k. We haven't gone ahead yet with a full quote, re-thinking it in the climate as there's a lot of work generally to do on the house. We're SE.