It will likely be the LED driver(s). Is the light control just on/off or does it have a dimmer function?
Often LED drivers use a technique called PWM (pulse width modulation) which generates electrical noise at a harmonic frequency of the VHF frequency. It is a black art to resolve - it may be radiated by the driver and picked up direct by the VHF aerial, radiated by the driver into other wiring on the boat that then acts as an antenna, or conducted by the driver into the LED wiring making the LED wiring act as an antenna.
You need to try and establish which form of propagation is happening. Maximum separation between interference source and VHF aerial is good. Seprating the drive from the LED wiring, or splitting the wiring may also help to pinpoint the problem, Ferrites on any wiring causing the problem may help, but you really need a box of ferrites and patience to see what works via trial and error.
On the plus side at least it is an obvious fault - I have had interference issues where a power supply knocked out the IF stage of a VHF - end result the radio wouldn't receive weak signals, but all testing on the VHF showed no fault. I hate EMC issues