(26 Nov 2015, 6:10 pm)R852 PRG wrote Thanks for your reply, this is all very informative. The numbering system makes more sense now. Appears to be a case of transferring existing numbers over to a new system and then filling the gaps with any additions to the fleet.

Put simply yes that is exactly how it was done Busways had a batch of 40 Volvo Olympians numbered 701-740 & the Volvo Olympian Prefix was 16, so 701-740 became 16701-16740 etc. 

The re-numbering scheme was done at National Level & was NOT done by individual Depots. The idea being that once allocated the vehicle would retain that same Fleet Number for its entire life making it easier to trace should it be moved elsewhere in the Country.

In years gone by if say a Volvo Olympian was allocated Fleet Number 938 in a Scottish Fleet & was transferred to Busways, it would have perhaps been numbered 741 following from how the Olympians were numbered in that specific fleet, whereas the current scheme means its moved but retains that same Fleet Number.