Rear extension - can anyone help?

[kateqpr]

I'm looking to extend the kitchen and dining room at the back of my house.
The work would require knocking down the old tiny brick utility room and the current back wall, and extending out the entire width of the house (which is about 23ft) back by about 6 ft. Probably with a flat roof.
Does anyone have an idea how much that would be? I've looked onthe internet and have seen forums that suggest it might be around £1400 per square meter.
Any thoughts gratefully accepted. Cheers
Kate

 

[fastJedi]

Prices are depandant on location

A friend of mine has just paid £16,000 for a 3.5m x 3.5m single story rear extension with a apex roof (South Wales).

I am currently turning in quotations in the order of £36000 for 40sqM single story extension (Glos)

Both are simple block and render construction with nothing much inside!