Mark is certainly at his peak during 91 - 96 tours on the guitar.
Whilst I do listen to OES shows a lot, alas for me the sound of the OES tour was a massive departure from that of the BIA tour and the Mandela gig.
Having literally worn out the tape of the Mandela gig, particularly sections of EC's solos, to then hear the radio broadcast of Woburn Abbey was a bit of a shock. People tend to focus on the Pedal Steel guitar which of course is a massive insertation, but I think the biggest change in sound was the approach to drums - clinical and formulaic. Whilst I really appreciate Danny's percussion, that was the first thing that struck me when hearing Woburn Abbey, along with the drums which are functional but lack the raw emotion of Terry's playing. Add that mix to a well behaved Phil Palmer and lashings of pedal steel at any opporunity and makes for a totally different flavour.