Faulty RCF ART310

Hi, I have an old RCF ART310 powered bin, after a couple of years of use it started exhibiting high levels of distortion, following a hammering at high volume. Both speakers checked out OK, and a scope showed a lot of crossover distortion, obviously an electronic problem.

This is the version prior to Class D, the LF amp is a fairly conventional beanstalk design, using multimosfets for output. In my experience, when this sort of design goes bad, there can be damage all over the place, replacing a small number of devices generally doesn't help. I've read that the output devices used may not be very robust so they are likely to be a good starting point, however if you do an incomplete fix the result can be creation of a worse problem.

Has anyone experienced a problem with this amp, and actually done a fix? Is there a small number of components where replacement has a good chance of solving the problem? Thanks for any thoughts...