I recently bought a new tensioner bearing/pulley from one of the well known Lotus part vendors in the US (very good guys...). It's $88 bucks from them, or you can buy the same exact bearing on RockAuto for $23 bucks. It's the same Flennor bearing number FS03299 (fits a Ford Transit Van) from either place.
1982 FORD TRANSIT Timing Belt Tensioner
1982 FORD TRANSIT Timing Belt Tensioner