I don’t understand what the UK is trying to achieve with this line of argument. Germany spent €375m funding BioNTech, ~20m doses of whose vaccine have gone to UK. UK spent £84m funding the Oxford vaccine, precisely 0 doses of which have gone to the EU.

(Loose phrasing there: should say “precisely 0 doses of which have been exported from the UK to the EU”, since exports are the issue at stake here)

You could argue I suppose that the EU has benefited from that £84m of the British taxpayer’s money through the ~30m AstraZeneca doses it has received from factories in the EU, but that seems a bit circuitous