For Rules of Origin, I would state the EU country you bought it from. They only want to charge you VAT when it enters their single market.
As for the French, they are being the usual charming neighbours. They are deliberately delaying and holding up parcels. BBC News story last night were they let £1000s of live shelfish go to waste just because the paperwork was 4kg out. Held another lorry driver up. Put his paperwork on a desk to be checked, they didn't even touch it. Told him he could go after two hours wating. The French then put pressure on Spain because they were being too lax. They are laughing at us because we are allowing smooth imports into the UK. Lovely partners the EU..see ya and good riddance.