wrote:
Back in '13 or 14 we had a very bad felted roof & looked primarily at EPDM
& steel. In the end a temporary job was done using bedsheets, bitumen &
sand without stripping any of the damaged felt. Last time I checked it
was still fine. Given that I'd take that approach again in future. Total
cost was under £25 & it was quick compared to a new roof. Just wear junk
clothes, they will get ruined.

Interesting, thanks. In this case it's at the front of the house so a bit
wary of conspicuous bodging...
(and DIY isn't an option in this case)

I came across:
https://job-prices.co.uk/flat-roof-cost-calculator/

which was 1.3-1.4K for a 3.5x6m flat roof with timber (optionally
insulation) in London/SE. Does that sound more plausible than the 2-3K
already quoted?

Theo