Common sense would tell me that the ‘equipment or modifications’ refers to items other than manufacturer, factory fitted options as these will be covered under the insurance group of the model of that car.
i.e. factory option Wheels = Covered
Halfords wheels = Not covered
If that isn’t the case, and as your query to Motability and RSAM only resulted in having the paragraph repeated back to you, then buckle in Motability because your email in-box is going to go into meltdown with requests for factory option paint/tints/packs/mats/boot liner/etc/etc!
? I will be remembered for nothing but had great fun doing it ?