Hi Ulf,
What I have done in the past when I had a problem with fuse 6 blowing, and not having the short 25amp fuse.
Was with tweezers carefully remove the metal fuse wire from the short fuse. So now you have a blank fuse with no wire.
Take a regular length 25amp fuse and again carefully remove the wire. Now attach the longer wire to the shorter
Blank fuse, attach the top and bottom cap, now carefully fold the wire between the caps for a secure fit.
It worked perfectly for me. Worth a go if like you can’t wait. Good luck.
DM