do you have a date for delivery in your order info?

once that date passes you can open an item not recieved case.

5 weeks from UK isnt unheard of, ive had items take longer, also much quicker. thats if the seller posted ASAP. 

if its comming by global shipping that can cause delays too.

what was the period seller listed as posting time in days? if he waited until the last day that would reduce the time its taken so far.

all you really need to do is make sure you open a case before your time runs out for non delivery.

paypal has the better time limits for that.