Yes 'HW' seals fit straight in and are far superior to the BSA items, the issue that you have is that the exit of the transfer port has a rough edge that needs removing or it'll just keep knicking the seal...
Here's what I did;
1) Make sure the safety is engaged...
2) Break the barrel and with the butt of the rifle firmly wedged in your groin/between your legs or whatever you're comfortable with (whatever way you choose just make sure it's wedged firmly as you don't want the barrel to snap shut with yer fingers between the breach jaws, BIG no no that one) continue to grip the barrel firmly and hold the barrel in the broken position...
3) Take some 1200grd wet'n'dry paper (before hand you need to make sure it's folded narrow enough to slide between the breach jaws) and some light machine oil and proceed to polish the exit of the 'transfer port' removing the burgh in the process, job done, no more knicks or slices in yer breach seal...
.22 S410...
.22 Webley Xocet...
.22 HW95k...