There are 2 things I can suggest and I have done both.
1st – Dismantling the forks.
There is a special tool for removing the inner piston and cylinder unit that stops the inside tube from turning. This can be done as follows without the special tube. The inner piston and cylinder unit has a 17mm hexagon recess in the end. I have a length of 10mm threaded bar which I have locked 2 buts together at one end. The other end I have bent over 90 degs. Locate the nut inside the fork leg and you cam then undo and remove the screw.
2nd – Forks assembled.
Remove the spring retainer and washer from the top of the fork seal. Using a thin string screw driver or similar drive it downwards between the outside of the seal and lower fork leg. Be forceful but take care not to damage the aluminium. Once it is firmly in, twist to get under the seal and lever the screwdriver down to force the fork seal upwards. You may need to do this several times in different places.
Once released slide it off the end of the fork tube.
To fit the NEW seal apply a little oil to the fork leg and gently slide it over the fork leg and into position over the fork leg. You then need to drive it into place. Slide the fork seal washer over the fork leg and rest it on top of the seal. You now need to slide over a collar/tube to tap the seal in place. I use a piece of old car exhaust pipe and tap it gently whilst rotating to prevent the seal twisting and getting damaged. Once seated remove the tube and refit the retaining spring.