hello,
you bought a land from an SC/ST. you gave the money but did not make registered sale deed. there is no proof that you purchased the land except maybe the cheque/ cash transfer.it is possible to register the property at this time. but if he refuses you cannot do anything except maybe filing a case of cheating and fraud.
moreover, I should inform you that in 1994-95, UK was in UP. so the land laws of UP were applicable. at that time you could not buy a land from an SC/ST if you were a general category. then if you are a general then the sale at that point of time would have been void.
regards