It is now a case of new tyres for old, and I have replaced them with Bontrager Race Lites. Now for the geeky bit:
The Race Lite Hardcase offers armor-clad flat protection without sacrificing high-end road feel.Dramatically reduce the risk of flatting with the triple flat protection of Race Lite Hardcase tires: the bead-to-bead woven construction reduces sidewall cuts; anti-pinch ribs eliminate pinch flats; and a Kevlar belt provides outstanding puncture resistance.
And the Hardcase's high-speed tread compound provides optimal traction and low rolling resistance no matter what the weather, so this tyre is equally at home training and racing. Dramatically reduce the risk of flatting with the triple puncture protection of Bontrager’s Hardcase technology
So now if I get mugged all I need to do is simply shout "Stab the tyres, stab the tyres" and can then laugh and ride off into the sunset as they have a Kevlar belt. But will they stop the flint and punctures? I guess I'll find out tomorrow.
And yes, saddest of all, here's a picture of them!