I swapped the cluster this weekend. Also took the opportunity to replace the crappy OEM-radio with a Bluetooth one. Used a 1-din dashkit for that, looks quite alright actually.
Nothing needs to be done to enable the replacement cluster. It’s plug and play. The mileage is stored in the cluster, so make sure you install one with slightly higher mileage than what you have as to not get into any odometer issues during the next MOT. I swapped my faulty 179k cluster with disabled check engine light for a unmolested one with 185k on it. Paid 40 bucks for it at a local junk yard. Those extra 6k in mileage won’t hurt the (non-existent) resale value anyway.