Loft conversion SW London - recommendations please?!

[Kingsroadie]

As per the title - have seen comments on here re most of these:

A1 Loft Conversions
Loft Rooms
Econoloft
Scott McCabe
Charles Grosvenor
Loftscope

Has anyone around got any first hand experience of them?

Also, (yes, I know it's very "how long is a piece of string), ballpark figure for cost? We would like to do a master bedroom and ensuite. The previous owners of our house have already had the plans drawn up and PP has been approved. The loft is currently a usable room (but would obv need to be extended back and to the side into the eaves) with flooring and electricity and a velux (and all the eaves cupboards) with a proper fold down loft wooden loft ladder. I assume the floors may have already been strengthened in that bit. This would help reduce the costs a bit I imagine. The back would be a dormer extension - I think that's what it's called - am useless at this kind of thing - where they extend with a flat roof out the back...

I was thinking around £40K?

Any help much appreciated! Thank you.

Try calling your local council (building control) to find out if they've passed any work by any of the companies listed above, recently.

Also try Trust Mark and check if any of the above are on their register.

If you get recommendations for any of the companies, do your own research too and satisfy yourself that the company knows what they are doing.

Be very careful who you ask to do your loft. There are rogue traders around. Once they get a foothold on your property and problems occur, there's very little you can do easily to get things put right. That's the law in the UK, am afraid. Very little protection when it comes to building work - you have more rights when you buy a vegetable. I wonder how that's been allowed to happen?