We simply do not know what the VAT structure shipping from outside the UK to Ireland at this early stage of the Brexit process will be.
At this time, as Garfield has pointed out, if you buy goods to the value less than €150 outside the EU and have it posted to Ireland, there is no additional charge.
If UK businesses deduct VAT on products shipped outside the country (Hattons for example has been doing this for years for orders outside the EU) then you will see a 20% discount on the sticker price. The would keep a lot of products under the €150 threshold. Paying an extra fiver on your shipping rather than using Parcel Motel will still see you making a saving.
There are a huge amount of variables to consider before declaring 'dark days ahead'. Will sterling tank for instance? Have read many economists predicting parity with the Euro, this will bring down the cost further. Not to mention altering tax rates post Brexit, which could include VAT. It's far too early to say.
It has as much chance being good news for us as bad news.
I do agree with Noel though, it is almost certain to drive the price of British outline models up further due to the weakening pound and I think we've seen this already with recent Hornby and Bachmann announcements.
Shipping from Germany to Ireland is not that expensive. I've done it myself. And most German websites offer English translations. I can't see them scrapping that over Brexit. The import threshold from Europe to the UK may be similar to what we experience from importing outside the EU. Again, far too early to say. There is always Google translate too which is nice and handy.
Maybe something like Parcel Motel will cease to be viable, but we will still buy stuff from the UK. I wouldn;t go all out with the doom and gloom just yet.