"I'm not sure what the Spanish are doing will even impact on the UK anyway. As with most data, it can only be shared within the EU and we are not part of that anymore"
Data sharing between the UK and EU will continue for now.
https://www.gov.uk/guidance/using-personal-data-in-your-business-or-other-organisation-after-the-transition-period
"Looking ahead to 1 January
2021Receiving personal data from the EU/EEA and already adequate third countries
The wider EU-UK Trade and Cooperation Agreement contains a bridging mechanism that allows the continued free flow of personal data from the EU/EEA to the UK after the transition period, until adequacy decisions come into effect, for up to 6 months. EU adequacy decisions for the UK would allow for the ongoing free flow of data from the EEA to the UK."