Six straps, lined so it never stretches, has adjustable fixing at waist for comfort, and six adjustable satin elastic straps with metal fixtures.
Suspender belt repairs - yes, I think the best way to do this would be to turn the straps you have there into loops that hold new straps. Trying to get the old straps off to replace would be a nightmare and cost more than a new suspender belt.
Pricewise
General leatherwork £40/hr plus materials and postage. Minimum charge 1hr, then 1/2hrly after that. - This job will not take longer than an hour
Materials
Elastic 2m x £1.85/m = £3.70
Clasps 6 x £0.50 = £3
Links 6 x £0.50 = £3
Postage, 2ng class tracked £3.19
Total £52.89