Conductor Rail Spacing

[Saint Johnstoun]

It is noted that the standard distance for the conductor rail, and therefore pickup location, on the LMS Merseyside EMUs was 16 inches from the running rail. I note however that the Liverpool Overhead was originally centre conductor but altered to outside at 19.25 inches. Does anybody have evidence as to what the original L&Y spacing was - it must have been 19.25 inches too, so Merseyside must have been altered to standard at some time but when?

North Tyneside was also altered to standard 16" at the time of the South Tyneside electification. This was also originally 19.25"