Loft conversion vs kitchen extension (plus bedroom)

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We live in a 3 bed semi and need an extra bedroom...

Can anyone give me an idea of the cost of a loft conversion (into a bedroom and bathroom with dormer) and an extension out the back ( that would make our kitchen bigger with a bedroom on top)

We are in the SE if that matters

We have put a deposit down ready for a loft conversion with dormer and en suite - cost £40k, all in.
We looked at doing a side return extension on our kitchen but estimates were around £60k (this would've involved moving all our drainage, plus steel to support the side of our house) We binned off this idea and are having our kitchen remodelled.
We are in the S.W

We've just done a double storey extension going out at the back of the house. We did consider loft conversion plus single storey extension but would've meant a compromise as we wouldn't have lots of headroom. It probably would have been cheaper both in build costs and also internal works / decor costs. Losing the back of the house, reconfiguration and extra space etc meant that everything (upstairs bedrooms / bathroom) had to be redone. I imagine you'd escape that just going up into the loft and had kitchen extension.

Our single storey extension earlier this year was about £70k - that’s including VAT, the huge sliding doors, wood flooring, decoration, a wood stove, utility room fit out, new kitchen.

We are in SE

Thank you for your replies

Basic cost of our loft extension in London in 2015 was about £37k. If you add in all other costs such as additional lighting and sockets, built in shelving, bathroom suite, tiling, blinds, decorating, carpets etc it’s more like £45k -£50k.