Don't prove the validity of the theory of 'sunk cost fallacy' OP. You've already paid for the trip you won't get that money back! So just forget the cost, and do the right thing for you and yours, plus the UK.
The only potential to recoup any cost, could be if your airline or holiday company cancels the flight, then you should have a valid claim - either on your insurance, or via ABTA, or even via your credit card, depending on your personal circumstances and the Ts&Cs.
Source : BBC website, today.
Headline - 1,500 more cases TODAY!!!
Coronavirus cases in Spain have risen by 1,500 to more than 5,700, public health officials say.
Spain is the worst affected country in Europe after Italy, which has more than 15,000 cases.
The Spanish government is set to announce a lockdown as part of a national state of emergency, according to local media reports.