Cynic was thinking very hard :
I've been thinking about using a Lidl smart charger with a mobility scooter
battery to power a dvr and a couple of security cameras since a local shop in
a shed was broken into after the mains supply to the shed was torn out,
leaving the cctv useless.
The charger seems to cut in and out according to voltage being between 12.5
volts and 14 when used with the battery and a light as load.
I'm asking myself if the voltage variations might adversely affect the cctv
equipment. Any thoughts?

Probably not, but it would be your risk to try it.