I emailed Olivia's & received a reply.
The locos are pre owned & according to the email don't have the problems which beset this model.
It seems the problems were the valve gear locking up & causing a motor burnout ?
I also asked if they came with some sort of guarantee but didn't really get an answer to that.
I'm tempted but I'm still not reassured. Its a big chunk of change to be risking on the off chance that nothing will go wrong.
Once bitten, twice shy & all that sort of thing.