Hankook Ventus V12's. Around £80 each from Camskill.
But that's £320, then you've got to pay for fitting, if you can find a fitter willing to fit new tyres they've not supplied? The OP has only £250.
I'd look around for premium part worns with a good 5-6mm tread.
I was going to suggest the same about some part worn, might not be everyone's cup of tea as you cant totally guarantee exactly what condition they're in but in my eyes its no different to when you buy a 2nd hand car is it, the tyres are always used then.
I've manged to pick up some great premium brand tyres for the same price as budgets before.