As long as you have your TRV, your documents (confirmation, contract, etc) and your plane ticket; you can then travel and enter Canada the soonest time possible. The VO at your POE will issue your TWP. It will have the conditions needed during your stay.
Completely different question: is a police check always needed when applying for a TWP, as a UK citizen? In several places I've seen it said that one MAY be needed, but I can't find any explanation of when it is/isn't.