As I've mentioned several times, there is certainly a pattern, whether intentional or not, in regards to the deployment of electric vehicles (probably the only interesting thing about them IMO) as you can see when I break it down. There may be other reasons at play but for this, I'll focus on these particular factors for this: location, age and/or ownership status of previous vehicles, Central London ULEZ (single deckers only) & operator change
23 - vehicles returning off lease
43 - runs into Outer London
46 - Central London ULEZ
49 - operator change
63 - operator change
65/N65 - runs into Outer London
69 - operator change, runs into Outer London
70 - Central London ULEZ
94 - meets none of the above factors
100 - Central London ULEZ
106 - operator change
125 - operator change, runs into Outer London
132 - vehicles not compliant for new contract, runs into Outer London
134 - runs into Outer London
153 - Central London ULEZ, operator change
160 - operator change, runs into Outer London
173 - operator change, runs into Outer London
174 - runs into Outer London
180 - operator change, vehicles not compliant for new contract, runs into Outer London
183 - vehicles not compliant for new contract, runs into Outer London
184 - vehicles not compliant for new contract, operator change, runs into Outer London
200 - vehicles not compliant for new contract, runs into Outer London
212 - operator change, runs into Outer London
214 - Central London ULEZ, vehicles not compliant for new contract, operator change
230 - operator change, runs into Outer London
235 - operator change, runs into Outer London
281 - vehicles not compliant for new contract, runs into Outer London
290 - operator change, runs into Outer London
312 - vehicles not compliant for new contract, runs into Outer London
319 - meets none of the above factors
323 - vehicles not compliant for new contract
357 - runs into Outer London
358* - runs into Outer London
360 - meets none of the above factors (was hybrid operated beforehand)
371 - vehicles not compliant for new contract, runs into Outer London
398 - vehicles not compliant for new contract, runs into Outer London
444 - operator change, runs into Outer London
484 - operator change
507 - Central London ULEZ
521 - Central London ULEZ
616 - vehicles not compliant for new contract, runs into Outer London (vehicles will be used on the 20 instead which also runs into Outer London)
C1 - Central London ULEZ
C3 - operator change
C10 - Central London ULEZ
H9/H10 - vehicles not compliant for new contract, runs into Outer London
P5 - Central London ULEZ, operator change
X140 - operator change, runs into Outer London
Out of the 47 routes either converted or confirmed to convert over the next 2 years (358 is up in the air, hence the *), 25 routes run into Outer London, 10 were converted specifically due to the Central London ULEZ & 3 are anomalies when focusing on those factors (94, 360 & 319). This leaves just 9 routes left that operate within Inner London and went over to electric operation mainly through an operator change or had non compliant vehicles or in the 23's case, the vehicles wern't being retained due to their lease. It will be interesting to see how long this pattern continues but I expect to for some time with Inner London holding on to a good bit of their compliant stock whilst Outer London continues the gradual move to electrics.