To be perfectly honest there seems to be a few vehicles that could do with replacing. The SPD's are terrible, DAF's on Lambton Worm & Waggonway, Certain MPD's.
The 'East Durham' MPD's at Peterlee aren't in good nic! I was on the 202 just the other day and it had terrible noises on the brakes, aswell as rattling, and really loud stretching noises you can bearly hear yourself think! The bus actually broke down temporaily at Dawdon and the driver tried a couple of times before he got it back on the road. And with the current interworking with 202/265/259/260 I dread to think if the bus made it Durham okay! So I'd like to hope Versas could be planned soon for the East Durham services.

RE: 56/20 Solars
It was strongly hinted by Rob earlier in the thread that 20 & 56 would both be getting deckers some time in the not so distance future. And I think the general consensus on here is that it can't come soon enough with a vast amount of journeys on both services running near or to capacity. So that will eventually lead to displacing 28 Solars.
I would like to see
13 go to Lime routes, the Renowns can then go to Doxford Clipper.
11 go to Lambton Worm/ Waggonway/71.
The rest can go Northern.