I possibly didn't explain myself well enough in my OP.
I would get enormous satisfaction from buying every single individual component and then screwing/bolting the entire box of parts together myself, mad as that might appear to be. BUT of course I have to consider my very restrictive budget, as such if it is going to be less expensive to buy a bike from the likes of
Decathlon, Merlin or Planet X and change a few things such as the cranks and the stem, then so be it.
At the moment, I believe I will need a 54 frame, fitted with 165 cranks and an extended stem due to my upper body length.
But in the mean time over the next few days I will compose a detailed list of my needs and see how it all starts to pan out................