Along with looking for more advice I also have something that might help others for a change

Now for the spare parts info if you find yourself needing something on the mainland. You might already be aware of them, but thought it worth sharing. I found Mecatechnic (https://www.mecatechnic.com/fr-FR), they have English speaking option, but it only seems to operate in the morning. I ordered the gasket from here and despite calling to confirm I had ordered the right part there website wasn't clear), they sent me the wrong gasket.
Next I found Serial-Kombi (https://www.serial-kombi.com), whose website is much better. I couldn't get anyone on the phone, but their email response was pretty quick (hours, not days). Just beware of using Chronopost for delivery, I paid 15e's for next day and got it 4 days later, after receiving 3 false tracking notifications and being lied to multiple times by their customer services about it's imminent arrival. Hence a week spent in Calais!
Cheers,
Peter