I'm probably being dense but why are food parcels being sent from the UK?  Don't Portugal and Spain have a rich and varied cuisine?  Admittedly their pork sausages and bacon are a bit different.  And I haven't come across haggis or black pudding.

Will I be able to bring in HP sauce in my hold luggage? Probably buy it in LIDL/ALDI

Is it true that these stores are owned by conjoined twins? Apparently that's why their stores are always so close together.  Just an interweb rumour, but no smoke without fire.

The book came from the a UK company who ship all over the world. I am sure they can sort out some paperwork for their EU customers, but there would still be customs duty and local administration costs as you say.

A similar problem exists I am told for people who use transport companies to bring out personal boxes of UK foodstuffs etc. In some cases the price of so doing has tripled.

Unfortunately this means you are responsible for the deliver and Taxes from Faro.

Another consequence of UK leaving the EU that may be visited on others resident here. For the past ten years or so I have been receiving, twice a year, a little package containing a paperback version of the European Rail Timetable, nice and easily through the normal post.

The latest issue has been impounded by Portuguese customs. In order to receive it I must provide my fiscal number, a copy of the order placed, a copy of of the invoice stating the cost of the item plus postage and a copy of the page of my credit card statement showing payment made. I will then be billed for customs duty and VAT on that duty. The book sells at £20.99.

Fortunately they also publish a digital edition to which I can subscribe. But I do prefer the print version.