As Unknownfate says, blank the numbers, I have been ordering from TRSI for over 6 years now without a problem.
On the subject of import tax, I have placed 7 orders with TRSI in the last 18 months and only paid import tax on one of those orders that was around 11 single volume files, the others that were 5 - 6 volumes (or brick equivalent) got through without any additional charges. The difference seems to be that the heavier packages always end up with Parcel Force so get charged and the lighter packages go through a different route and sometimes slip through the net.