Hello I am moving to BC shortly and will want to forward any post that arrives in the UK but I won't have a permanent address to send it to when I am first there so where do I send it ? Can I get a post box before I arrive or how can I do this ? Any ideas ?

Perhaps you could have it forwarded to parents/relatives address in the UK then once you have an address/PO Box in Canada then it can be forwarded on. Canada Post does PO Boxes but require you to provide Govt ID to rent one.

How do I rent a Postal Box?
Bring government-issued photo ID to the post office where you wish to rent a postal box.
https://www.canadapost.ca/web/en/kb/...t=maildelivery