Doors, lights, radio, horn etc. all working but power/start button non responsive not even a click,, tried 2 fobs and (key) blade in backup ignition on steering wheel housing again no response,,,, any suggestions on rectifying problem?

I once had a very similar-sounding problem with a 2012 Mk3 1.0L Ecoboost. It turned out to be the battery. For some unknown reason it seemed that the ECU had detected a low battery capacity** and had disabled the starter (I can't imagine what Ford designer thought that would be helpful). It wouldn't even work after an overnight charge but replacing the battery fixed it.

** Note I said capacity, not State Of Charge. Batteries slowly lose their A-Hr capacity over time and can also develop partially-shorted cells if paste falls out of the plates. As I said it still wouldn't work after I'd fully charged it overnight.

Thanks,,, sounds pretty much same, I know my battery not holding charge well and I prob need to replace soon anyway so I'll try that route first, I thought it may be another reason as no response from jump leads either

It might be something else if you were using jump leads from a running vehicle. Do you know how old the battery is? It must have been renewed at least once on a 17-year-old car.