Preserved Mersey Class 507 train fluorescent lighting

I was so pleased to see this image (credit class 507 preservation group ) of the fluorescent lighting used on the class 507 electric multiple units that ran on the Merseyrail 3rd rail network for 46 years, 1978-2024. The inverters that are powered from 110vdc can be clearly seen. This unit is 507001, has been preserved and is currently at Derby Litchurch works. Prior to a refurb around 2004, the lighting was provided by T12 4ft 40w lamps with no diffuser, just an arched plastic cover over the lamp holders to prevent unauthorised removal. Following a refurb, the 5ft, 58w 2700k fluorescent tubes were integrated into the ceiling. The diffusers are have quite unusual curved, I think it was to represent 'M' for Merseyrail.