As long as you travel before 31 December 2020, there will be no consequences for customs as the UK and Portugal are both within the EU Customs Union, VAT area, etc, so there are effectivley no restrictions on personal goods between the two countries.
As for if you can travel with such items - the general guidance is to consult your airline's and airports on ...
The Visit Portugal COVID page list the following rules which are currently in effect. Of course, these rules could change at any point as the situation progresses. (Bold emphasis is mine.)
Flights to and from Portugal
Air travel to and from Portugal is allowed to:
European Union countries;
Schengen Associated Countries - Liechtenstein, Norway, Iceland, ...
Caveat: As you said, getting the straight scoop on this is not easy, and is rapidly changing.
As of July 2020:
No tourism from United States
Yes tourism from EU, Canada, and over a dozen other countries.
Portugal had re-opened tourist (“non-essential”) travel from the US in May-June 2020, but that has been stopped in July 2020.