(25 Feb 2018, 8:10 pm)JP6004 wrote They cant do anything about black cats loop or green arrow until 2019 because of restrictions placed by the council after tgose buses received modifications to upgrade them to euro 5. I would imagine that all the above services will receive new buses after the specified date to allow the solars to be withdrawn

They can certainly get the ball rolling with the business case, financing or planning of replacements though (if it isn't rolling already).
Depending when in 2019 the restrictions are lifted, the 54 plate Solar's will be hitting 15 years old.
Appreciate some older examples are still kicking around, such as Chester's 52 plates, so I expect the better 54 plates to hang around at least towards the end of 2019 or in to 2020.
By that point, the Omni's will be getting closer to 15 years old and I can't see them lasting too much longer after that. Certainly a max of 3 years.
Compared to the Solar's, there are fewer Omni's in the fleet. The cost implications of sourcing parts for the Omni's, versus cannibalising older Solar's may impact on their lifespan. I can't see them kicking around as long as the Renowns or Solar's. Partly because of the smaller pool to salvage from.

A lot of vehicles to replace under the current PVR.

If we see further changes or route consolidation, then maybe we won't see a like for like pvr replacement.