It was in yesterdays Daily Mail ( so it must be true ) that a typical holiday daily spending costs 9% less in Portugal than in the UK.

The UK is £71.33 , Portugal £65.21 ( other Holiday destinations ranged from Bulgaria £40.88, Cyprus £75.39 ).
Portugal was mid table.
It did not give exchange rate comparisons so lets assume they were at current levels.

Given the current UK weather this could explain the current surge in last minute bookings

Yes i read that as well, however, not bothered how much it costs cannot wait to get there, two weeks and counting

same reason so many Irish go to CVO, reckon it's a least 30% cheaper than Dublin