Clicking sound at bulkhead Fabia 1.6 TDI

Apologies if I’m posting in the wrong section- new to posting but have been reading the forum for years. I recently recharged the battery on my 2011 Fabia 1.6 TDI as it had been sat for a reasonably long time un-driven over winter. When I reconnected it there was no issue at first but now I’m getting a clicking sound at the bulkhead when I turn the ignition off. It sounds like it’s behind the sound deadening at the top centre of the bulkhead. At first I thought it might be an issue with the alarm. It sounds a bit like a relay/solenoid clicking in and out and is loud enough to be heard outside of my car. When it first started it was reasonably slow and only occurred after the ignition was off for a few minutes, but a few days later it’s gotten more rapid and sounds a little bit like the an indicator tick and happens almost immediately on turning off the ignition. It stops again as soon as I turn on the ignition and through some combination (which I’ve yet to fathom out) of opening the bonnet and locking/unlocking the doors using the remote I can get it to stop which made me think it might be an alarm issue. I’ve managed to capture a video when it first started. It does get more rapid than this after a while.

https://youtu.be/QibrplJoV0s

Any ideas/help appreciated to prevent a trip to the garage.