I have a 30 that is used regular and at the time of sourcing it I recall all the advise I had heard and read about. (what models to avoid, what to look for, how to tell its coutry of origin etc). Just wanting a few tips from other 45 owners.......

How to tell if it is a UK bike, what to look for on the VIN plate etc?
Where there any major differences from one year/model to the next?
Any years or models to avoid?
Thanks in advance, will let you all know how the viewing goes.