I used to skate there now and again and never really liked it- expensive, lots of entitled kids and coaches taking the money, staff chatting to their mates and showing off. Not been since lockdowns. Alexandra Palace is not perfect (where is?) but I have always found it pretty decent, some good coaches and management, ice is reasonable - and the building and the setting are exceptional. Just a bit more awkward to get to as it’s not right next to a station. Slough I’ve been to only once so hard to comment other than the ice was fine and I doubt they have issues with it as it’s pretty new. Slough is a bit of a walk from the station but the parking is free. People have said nice things about Bracknell. I have some personal experience of other London area rinks (MK, Romford, Streatham, Chelmsford) - let me know if they are of interest. Some places might sound far but with fast trains and rinks near stations you have a few options. There’s a new rink at Lee Valley but I’ve not been.
Happy skating - I’m off to Romford tonight for my 4th skate in as many days.