Strange clicking sound coming from engine bay

We have a much loved 2014 Skoda Fabia 1.6 TDI (105) which has been a rock of reliability in the time we have owned it (since 2017). Recently though it has started to make a weird ticking sort of noise which appears to be coming from the nearside close to the top and above the battery (see video).

This started about 2 months ago and has gradually got a little worse. I don't think I notice any other effects except perhaps a slight dip in fuel economy although even that is hard to tell as we have been forced to do a few more short journeys of late when in the past we would only do weekend long jaunts of 50-80 miles and getting 70mpg.

Anyway, what do you think and should we get this checked out?