It could be a bad earth connection at one of the light units. Such faults can be difficult to find and correct unless you have experience of car electrical systems.
Welcome Jonathan, and thanks for joining.
For what it means:-
If I was in the market for this model, I was steer a wide berth around this particular example - at any price!
It might have got a pedigree, but I would not want the risk of it biting me - or my wallet.
Kind regards,
Gareth.