Stova in Carshalton.
They are expensive but if you are considering wood burner, they actually know what they are talking about (German origin)
We are in smokeless zone so you should buy a clean burning stove, there's a list from Defra of stoves that meet this spec. (we've got a Swedish Handol). These clean burning wood stoves tend to be more efficient so ultimately pay for their extra cost...worth getting your chimney lined if going this route. Stove won't really save you money unless you have free/cheap wood, think of it as a very low maintenance pet which gives a much nicer type of heat than central heating
I don't know if it's because we historically have preferred mixed fuel stoves (burning coal and wood) but there's a general lack of knowledge and expertise about wood burning. I've been told absolute nonsense in several reputable stores selling stoves.
Scandinavia and Northern Europe have a long history of wood burning and (oddly enough) tend to make the best most efficient and IMHO beautiful looking stoves with lovely big viewing windows
Clearview are good solid uk-made stoves - often tend to be mixed fuel - have been described to me as a landrover...make of that what you will.
Average builder may not be up to the task, though if you are comfortable there's an entire dedicated Building Regs document to wade through ( with the standard contradictory statements that you find in Building Regs).
One thing you must do, please to get your installation done (at very least inspected ) by a HETAS qualified person.
Carbon Monoxide is nothing to trifle with.