With my first order kit, the total value I paid for the kit was declared over the four packages I received from ANOVOS, so you will not get overcharged. If you are looking at avoiding paying tax on an item, its somewhat straying into illegality- not necessarily the best discussion to be had on a public forum! The last package I received from ANOVOS had a delared cost of $50, which was the neck seal, but had to pay £25, most of which was a handling charge. There seems to be no rythm or reason to it, I paid £80 less duty on the helmet than my mate Dave did on his (both from ANOVOS, both declared at a value of $700) whilst I paid £40 more for the armour. Unfortunately nowadays, everything over a value of £20 has a charge attached. When I started this hobby 11 years ago there was a good chance of not picking any charge up on its way through unless there was a significant value attached.
Customs charges into the UK are all over the place, it depends on what the item is, where its from, what its made off etc. What I find annoying is having to pay a handling charge for each item that goes through customs. Isnt that what POSTAGE charges are for!?