I've bought a few things from Japan and the only hold-ups have been at this end, usually after it arrives at the airport and they decide to stick their thumbs up their arses instead of getting on with it. Shortest delay was 2 days, longest was nearly two weeks (10 days IIRC) showing on the tracker as "assessment for Customs duty" or some such nonsense.
Expect to pay 6.7% import duty, VAT at standard rate calculated on the total (yes, VAT is charged on the import duty), then the carrier's Christmas bonus for their paying the fees on your behalf despite you not having had the opportunity to pay them yourself. That charge varies but is usually somewhere between £8 and £15. ParcelFarce International are the best for that, having two charges of £8.95 and £13.95 - which you're charged depends on whether your item is for 48 or 24 hour delivery and they don't even deliver it, you have to go in and collect it.
It's ridiculous as you've already paid the seller for P&P, including carriage to your door but without the backhander, the parcel company won't let you have your property. I've complained in the past but the law was changed a few years ago to make charging a fee for an unsolicited service legal in these circumstances. I find that if the PF person is particularly smug about it, explaining that you know it's the law and that they don't have the authority or ability to do anything about it usually wipes the smirk off their face.
Yeah, it's a bit of a bugbear of mine.
