right..
get the wheel up in the air.
take off all the plastic, hugger chain guard etc
pour warm water over the plastic strip. dont burn yourself.
cut the part that goes down the inside of the swing arm.
pull like buggery on the bit that bolts to the swingarm. 5 mins and it will come out.
as ever refitting is the reverse of removal
lube the new chain strip up with vasaline and the swing arm as well first.
if you have a speed4 with a hugger fitted. cut the bracket that bolts to the chainguard mount.
now you can either a)remove the wheel and fit your new strip. or b) cut the back bit again.
now swear a lot as you try and fit it