Like that saints one for the WCC, but Home Bargains! I know it's been done to death on here but I think they should have looked for someone else for this one off match.
If the vibrating is when you are going quite fast 50-60-70mph it could be a simple thing as wheel balancing. But if you're in a hurry to get it sorted you may be back to the same problem of when you can get it booked in. I'd ring round again and see if anyone can just check the balancing, explain you're going away but try not to sound too desperate.
Do you have another service centre you could go to? For a second opinion type of thing. There are quite a few centres that will do a free alignment check, and just ask them about the tyres.
Knew a bloke who was a merry flag waver, sadly no longer with us, he hated Ganson with a passion. Said "he stood on many peoples toes to get to where he was", and he was only a Ref. at that point.
Getting train from York, lad jumping on at Leeds. Into Manchester just before 12, bit of dinner and then on to Old Trafford. Sitting in the Alex Ferguson stand 2nd tier.