Extension or conversion

[REBM]

With things and prices the way they are, wondering if anyone has any recent experience in the NE of England with price difference between a loft extension with a dorma or full double story extension? Ideal need an extra bedroom and toilet of sorts. Original plan was loft extension with en-suite but I've also heard that a loft extension is expensive for not a lot of extra space?

Loft extension will be cheaper. But a good two storey extension should feel more natural with the rest of the house. Loft can be converted later too if wanted.