Advice needed on garage repairs please

[Jens]

Long story short, I had the car in to a BMW specialist last week to fix a CEL, it was throwing 2882/2883 codes - fuel trim bank1/bank2.

They diagnosed a vacuum leak and replaced the cam cover at a cost of £480.

I've had the car back for less than a week and < 100 miles later I have CEL and 2882/2883 codes back the night before the MOT (at a different garage).

Where do I stand?  Can I expect a refund, even partial for the previous "fix" or do I just have to suck this up and chase the next ghost round the engine bay?

Pretty PO'd about it to be fair.  Hoping I can clear the codes in the morning and sneak it through the MOT, but that's a side issue really.

TIA

[dj123]

Did they say it'll definitely clear the codes? You still paid for the work/parts that were replaced. If there's a further issue elsewhere in the vacuum system causing the codes, that's not on them. 

[Jens]

They seemed very confident they’d found the problem and when I asked they did state it would fix the issue. They’re now using more vague language. 
 

If there’s a further issue in the system I would have expected them to find it, after all isn’t that why one employs a specialist in the first place? They’re meant to have the equipment, knowledge and experience to find the bugs and squash them. 
 

Work and parts replaced was done at their recommendation that it would fix the problem. 
 

Replacing parts and hoping based on a best guess is something I can do myself. 

[dj123]

I would bet that at the time that was the offending item they thought was potentially causing the issue, and offered the resolution. It may be worth having a discussion with them of sourcing the leak, at potentially a discounted rate if they agree they do not achieve the desired result. 

As you've discovered it's taken time for the fault to re-appear. So a garage which does not have the time to drive your vehicles for miles is not going to always be able to fully check, or replicate the fault.