Hi Tony
Pleased to see you are getting your hands dirty LOL
Try giving these a shot
E-Trakka Fasteners Ltd Nuts & Bolts
Tel: 01670 545552 Unit 35, Grasmere Way, Blyth Riverside Business Park, Blyth, Northumberland NE24 4RR
Map and More about E-Trakka Fasteners Ltd ()...
Never used them but they are local to you
Tell them you want a high tensile bolt the same size as the one you have (+ the snapped off bit)
The hole being tapped means its had the thread re cut
As for cost I would hope you get change out of 50p
Steve