I was pinged by the NHS COVID-19 app just after 1 o'clock this morning. Following the app's advice, I took an LFT test and, for extra precaution, a PCR test also.
I decided to stay in my room for the day to be on the safe side and to protect my fellow residents; the care manager informed me that I would be subject to daily LFT tests for a week and in isolation until the result of my PCR test came back anyway.
I feel absolutely fine so I am presuming (and hoping) that this is all for nothing.
UPDATE: The PCR test result was negative.