I am ordering a textile jacket from a Canadian supplier and wondered what the import tax and VAT would be?

You'll have to phone Customs and Excise. Good luck getting an answer though. Many yrs ago I was sending a gift from Canada to UK and I wanted to pay the duty etc up front so the recipient didn't have to. Could I get a sensible answer from anyone - NO. Even called the local Post Office next to the recipient's home, couldn't give any ideas either.She had to pay and I refunded but it wasn't the same.