--Latest update--
First off I got the tyres sorted and the bike passed it's MOT.
Only just though. The main reason it nearly failed was because of worn tyre valves. When I took my wheels in to get the new tyres put on the lazy tightwads didn't change the damn valves. I know I should have checked but at a glance they looked ok.
It's hard to believe that so called motorcycle mechanics will risk the lives of bikers by holding back on a 50 pence valve, especially when they are charging £15 a wheel (or more) to put the rubber on. If you ever take your wheels or bike in for a tyre change, mark the valves and make damn sure they are changed every time.
To the garage concerned, I'll be in touch!If you fancy doing your own tyres, check out this demo
http://www.youtube.com/watch?v=anyY0UO5gqkI have also found an expert to sort out the carbs and generally give the bike a going over to make sure it's safe and in tip top condition. Sure, I could probably do many of the checks myself but this guy knows his Honda's inside out and hopefully won't charge me a fortune.
Give it another few days and this Hornet will be ready to hit the road!