Solo guitar on MFN and Heavy Fuel are pretty well over driven.
Yes, I am aware
But there are no solos on the album versions of those songs. Famously, Mark was encouraged (by Dorfsman?) to take a proper solo on MFN in the studio, but preferred not to. Unlike live, where Mark played solos on MFN in '85, and both he and Phil played solos on the OES tour.
The outro of MFN is one long solo - in fact TWO solos panned left and right! Mostly the same but sometimes they differ and it sounds cool 
In a sense; we could quibble about this, but you all know what I mean
On the live versions, he plays typical rock solos, far removed from the riff, while on the album, he "solos in his own rhythmic way" (paraphrasing Dorfsman), only venturing briefly away from the riff.
In 2005, Guy said that only having Mark on guitar was a step back to the album version, but this never quite made sense, as there are two guitars on the album (like you say, Dusty). Relegating Richard to cowbell must have been one of the least flattering treatments of an ace guitarist ever...