Loco building service (OO), South Yorks, East Mids

[Chuffinell]

Anyone know of, or can recommend a good, reasonable loco builder/converter? (OO scale)
I need a couple of specific locos which aren't available either RTR or kit-form, but it may well be feasible to convert from locos that I know to be similar. Beyond my capabilities, so reaching out (and shelling out!).
Was thinking not too far away, so East Midlands/South Yorkshire area.
Thanks in advance

[Bigmet]

It might help 'spring' a suggestion if you include more of the relevant detail: in particular what scale/gauge is required , the subjects you have in mind, specifying if a fully finished livery is required; and if so what livery, and the time taken from order to fulfillment and the financial terms . My past experience is of a fair amount of specialisation 'out there', and that may still be the case.

[Mountain]

What might help is to talk to those who are involved in 3D printing?