Not sure if anyone else does track days but I found out today that Opentrack have pretty decent reductions but today only. They haven't fully populated their calendar for 2021 but there are quite a few days including Anglessey, Cadwell, Croft, Castle Combe and Thruxton and some evening sessions at Donnington and Brands amongst others. I've booked Combe in April, July and August. I did Opentrack's Combe day in October (see GTMOC newsletter). It was a well organised day and as well as being amongst the cheapest I've found they don't overbook the days so plenty of track time and they also offer free photos and free tuition. The April day is only £120 (sale price) for a whole day of open pit lane so a complete bargain.
https://opentrack.co.uk/view-dates