Surely it depends on the cheque in question. If its from natwest, to natwest, it will be quicker than X bank to Natwest.

Paid in a 3 year old cheque last week!
i have a petrol cheque from work that i need to clear by friday. it will be paid in today whats the chances ti will be cleared in time?
they recon 7days. i swear its been quicker before
That may not actually clear though, cheques are generally only valid for 6 months.
Burnsy