classic motorcycle forum

 An acquaintance of mine in my home country has couple of 1930/1920’s vintage bikes (mixed brands -mostly un-restored, but in very good condition). He happened to E mail me some time back asking if I was interested in buying any of them. Most of his bikes belong to long gone era of “Arial”, “Norton”, “Matchless”, ”Enfield” (all British) etc…I ‘am pretty sure that I’ am going to buy at least one. Just wandering, where I could get a prices reference for these old British bikes? Any pointers would be helpful since I have no idea how much is expected.
Thanks,
FordMonster