I did get that your bike isn't a twenty but got a bit carried away as I often do

All you need to work out is what size the headtube on your bike is - 1" or 1 1/8" and whether you have a threaded or aheadset type of headset. Once you know that you should be able to source the kind of fork that suits the bike and your pocket best - or go for the suspension hub or wider tyre options.