Hello Albie
Some stuff on mileage checks here
http://www.bimta.org/MileageChecks.asp
Supra's are very reliable, a service history is very desirable though.
Try to get a standard car that hasn't been modified too much, wheels and exhaust are okay.
I think you've really got to be prepared to travel to get a good one, personally I wouldn't buy one from a garage. They're there to make money from you and you'll get more value for money buying privately.
If you do find a car then post it on here, a local member with some experience would hopefully look at a car with you .
Very true!