Given the 'Jaffa Cake' livery was on the 411s and the first refurbished 421/7s, it's fair to say all CEPs/BEPs/CIGs/BIGs would have gained it. The retained REPs/TCs likely as well, and the 442s (I need to find the artist impression drawing). The 309s obviously got it as well (branded 'Essex Express'). The interesting question is whether loco-hauled stock would have got it as well:
- West of England line (and Class 50s) - likely yes
- Cambridge loco-hauled sets (Mark 2s, Mark 1 RMBs and 47/4s) - possibly given the distance and inclusion of buffet facilities
- Northampton Line 'Cobbler' sets - would have thought the Blue outer suburban livery more likely
- Thames Valley sets - likewise would have thought the Blue outer suburban livery
On an EMU front the 305/1s, 313s, 315s and 319/0s would have likely got the Green livery being all Standard Class. That would likely have applied to the EPBs and 455s on the third rail as well as all Standard Class.
For the Blue outer-suburban livery this would likely have been the most widely used - Class 302, 305/2, 307, 308, 310, 312, 317, 413, 414 and 423 for EMUs and probably the whole of the DMU and DEMU fleet given the First Class provision (as well as the two loco-hauled service groups above).