Sorry to dissapoint Billy but my 1st order via normal post took 5 weeks mate. I didn't believe him at the time but he did send it within 48 hours it just took forever by normal post. Since then everything has come by FedEx, costs more but if the order's nearer £100 then it's worth it to get it within a few days.
I always ask Jarvis for Fedex - my last order took a few days ... it is probably stuck with good old parcelforce - there is a way to track with japan's ems (there tracking is in english!) but I reckon you are stuck with our fleecing royal steal ...
Yes, delivery time with standard mail can be as much as 4-5 weeks in some rare occasions so I would not start to worry at all. This is really down to where Jarvis has his warehouse, which is not Japan by the way.
I never use standard post anymore and now only use FedEx or EMS.