Make something people want. People don't want metric. Give up on it... The UK is similarly un-metric. Be proud of it!
Asking for 100g of strawberry bon-bons, rather than "a quarter of strawberry bon-bons" just makes you sound like an idiot IMHO. Also obviously milk is by the pint.
As far as I know though the case against selling food by imperial measures was dropped by the EU.
I agree it's a mess that needs sorting out. Leave people to use what they want to use.
Just like the fact you can happily discuss units of measurement with someone from a foreign land.
If an entire country uses a particular unit of measurement, leave them alone to continue using it in peace.