Has anyone made there own discrete winch bumper before? I’ve seen a couple that have been made on Facebook but wanted peoples first had experiences with them and if there much of a hassle to make and fit?

If you have access to 6mm sheet, a press brake, nibbler, pillar drill, good welding gear (NOT MIG!!), and you're handy with an angle grinder, then you should have no problems at all, as the material stresses on the finished product would be such that any component failure cpould be both catastrophic and potentially fatal, so let a professional build it for you.
That's why we buy them ready made 'off the shelf'