Intermittent engine Tapping noise

Every now and then there appears to be a tapping noise coming from the engine. It’s not constant.
Any ideas what this could be please?

 

I had one like that, it was the cover over the oil pump chain in the sump.
Other common rattles from them are the timing chain, variator, and the fuel pump can follower.
Have you had the sump off for a check of the oil pick up?

 

Thank you for your reply. I will get it checked