In the past, any order I have placed with Playmobil (UK), whether it is an order from the website for sets and DS items, or a list of parts sent in by email, has been sent to me using UPS. I have always assumed (and I could be mistaken) all the shipments come from Germany. The parts orders certainly do. I thought the UK branch in Essex just processed web orders and parts orders which were filled from Germany. Now I think of it, that is probably wrong. Occasionally there are 'damaged box' sales by PM(UK). So there is perhaps a UK warehouse for current sets. Which destroys my argument that if Geobra can still supply sets without faffing around with customs duties, they should be able to sell spares. What I don't want to see is a UK-based spare parts depot, which is occasionally restocked from Germany, because this would lead to the same atrocious service experienced in North America!
About your 6879 malformed wheel, drbatesy, I have always found PM(UK) to be very good at supplying missing or defective parts free of charge. That would seem to fall outside the usual spare parts service, which is described as being for lost parts or for parts to complete secondhand sets. I don't see why you should have to wait. Perhaps you should ask for a complete replacement set?
I am a little uneasy with my own lack of restraint when describing the negative effects of Brexit on my Playmobil hobby, but I will say I have yet to find any positives.