Replace BB cartridge in eccentric block

[MichaelW2]

My hub gear bike had an aluminium eccentric block which rotates to adjust chain tension. The square taper cartridge bottom bracket is screwed into the block.

I need to replace the BB which is over 12 years old and probably siezed in place.
I can't wrench it out in situ, the eccentric will just rotate.

Any ideas?

 

[I like Skol]

Have you tried yet? Before worrying about the 'what-ifs' I would try removing the BB to find out the state of play, before trying to fix a problem that may not be an issue.