If the consignment exceeds a certain value, then there is an import duty on top of the VAT etc. I seem to recall that the rate is 2.7% for safety razors, and the threshold is £135. When I bought my Timeless kit of several caps, bases and handles in one go, the total came to around £475 sterling, so I took a caning on the VAT, paid some import duty, but only £8 to Royal Mail.
My logic at the time was that if I bought what I wanted piecemeal, then I might just miss the import duty (not too big a sum), but the VAT would total up over several consignments, and of course it would be greater than on one shipment, as VAT is charged on the shipping cost as well as the goods. For example, if I bought three separate shipments, at a shipping cost of, say, £10 each, the I would be paying VAT at 20% on £30. If I bought in one shipment, which, for example, cost £15 because of increased weight, then VAT would be on £15, not £30. I would also pay just one fee of £8 to RM for the thing.
I bit the bullet, and it was my single most expensive contemporary razor purchase, but they are superb pieces of shaving kit.