*update* picked her back up this evening, the following has been completed by the garage:
Work done - investigated blue smoke from exhaust and excess oil consumption, suspected engine breather fault,
Replaced rocker valve cover,
Replaced oil separator in rocker cover,
Replaced leaking vacuum pump,
Topped up engine oil level,
Adjusted free play from handbrake,
Road tested - OK.
Hopefully, this has resolved the problem and I can finally start enjoying the Z! The invoice was for £833.58 - Im relieved that I haven't footed the bill!