It seems to be a running theme around here about 75% of the time I try to engage professionals for anything, be it a plumber to service our boiler or a machine shop to face a manifold which I think I was trying to do last time.
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Following a recommendation on another forum, the heads have been dropped off with Headline MK to be cleaned, checked over and if needed skimmed. Seemed efficient, polite and a refreshingly old-school sort of place. Figure this just makes the most sense as it means that I know for sure that the heads are both properly flat before I put things back together, and they have far better equipment to check that than I do! If they're good, they'll also get the job of inspecting and doing any rework needed on the Renault's head when that comes off. Given the response I've had from a lot of so called professionals around here, getting an immediate cheerful "Yeah, that'll be no bother" was kind of refreshing.
Given I have suspicions about the quality of the workmanship when the heads were fitted last time (the gasket residue isn't from the gasket I've just removed!) Getting them checked to ensure they're actually flat just seemed a smart move.
Otherwise I've been running around like a headless chicken for 95% of the day today. Only thing I did was take ten minutes to see whether it's worth spending any time on cleaning the valve covers up a bit as they're quite oxidised in a fair few places. The before and after of a really quick skim over suggests that yes, the end result in the engine bay will be worth it and will make things look far less scruffy.
We don't need a blinding mirror like finish here, just looking tidy is sufficient.