I am in the UK and not aware of any delays here. Was the price of the item over £15 ( about $27 CAD)? Anything over that value is subject to import tax and instead of delivering the parcel, Royal Mail mails sends a card telling you to collect the parcel from the local sorting office and also tells you how much tax and handling fee is payable on collection.
This is what the card looks like -
http://www.royalmail.com/personal/help-and-support/Ive-received-a-card-asking-for-a-paymentSo if it is going to be subject to a fee and the buyer hasn't received a card yet, it might be worth them popping in to their local sorting office to check if the parcel is waiting for them, just in case the card wasn't delivered.
If the value is less than £15 it should be delivered as quickly as possible, but of course it still has to be checked through customs. (The import vat rate is 20% and the RM handling charge is £8 so they don't let many slip through the net unpaid!).