Technical Twinair timing chain cover: labour cost to remove and refit.

[loserscar]

My 2011 Twinair has an annoying oil leak.
It could be from the sump seal (no gasket), or the timing chain cover (no gasket).
My mechanic can quote on the sump and suggests I try that first @£150
According to online, early Twinairs didn't have enough sealant applied to the timing chain cover where the head gasket is, and this is known to leak.
I asked at my local dealership, and a mechanic disappeared for half an hour and then quoted £750 for resealing it.
It doesn't look like he could look up the labour cost on his system if he took so long, and his estimate seems a bit hefty.
It's looking like Twinairs aren't supposed to ever need the timing chains replacing, so I can't find the cost of having that done either.
So, here's a long shot....
Has anyone else had the timing chain cover removed, resealed, and refitted?
And if so, what did it cost?
I know it won't exactly be cheap as space is tight, and my mechanic hates using sealant instead of a gasket.
Three quarters of a grand seems a bit excessive though.
Any thoughts?

Ta.

 

[jrkitching]

Any thoughts?

How bad is the leak? If it's more of a weep than a leak, you could just leave it, keeping a close eye on the oil level.

If you buy a drip tray, you'll have quite a bit of change out of £750.

Personally I wouldn't have much confidence in a garage which couldn't tell if it was leaking from the sump or the timing chain cover. And if their plan is to do the sump first simply because that's the cheapest, with no guarantee of a fix, I'd be looking elsewhere.