Cam Chain or Oil Pump?

[A-F]

Hi - First post so please be gentle.
My 06 car is very noisy on tick over - fairly common as I understand it, a sort of rattly valve train kind of noise.
Its been like that for about 2 years but is getting noticeably worse. I have read-up and based on the info I found assumed I needed a new cam chain and tensioner. However I have now spoken to a VW independent specialist and he suggested that it is more likely to be a an oil pump issue and has quoted me £2000 to fix it.
The quote seems fair but its the diagnosis that I want to check - is there anyway to check the oil pump?
Has anyone else has had a similar issue?
Should just change the chain first and see if that helps?!

[doylebros]

Start at cleaning the sump and oil strainer,get them to check for metal particles in the oil removed and sump internally, if it comes back clean then likely hood it's the chain and tensioner.