Hello Dave and welcome to the site,
Looks like you've got yourself a Benford MBR71 with a Lister LT 1 engine (mind your wrist).
From first glance it looks like your drive rubbers have failed behind the chain drive casing.....it also looks like the the rubbers on the opposite side have already been replaced ( the easy side). So i would start there to find your drive fault.
Sorry but from my really poor memory i think you will have to do a fairly large strip down to get to these, by removing the opposite side to the drive chain side (left hand side) and then pulling the drum away from the drive chain case.
Heres a link to one supplier so you know what you need and the rough prices.http://www.lsengineers.co.uk/small-plant-spares/heavy-plant-spares/bomag-benford-spares.html
These parts are still readily available because this roller a similar roller is still produced under the Terex name with an electric start. There are many other suppliers if you give it a google, as this is a common fault.
Richard (also a newbie)