Is there a BASIC TRAVELLERS ALLOWANCE required when flying from UK to CANADA

No, sounds like you have been caught up in one of the millions of dating scams out there.

Give us the story, you meet someone on line, talked to them for a few months, they are in love with you, ( or they have gold or diamonds to share if you help get them out of country)

They needed money for passport and visa, now this money, perhaps plane tickets.

Next they get sick or get robbed.