Advice before i buy please new member, oil light

[spongebob]

Hello everyone.
I have only just joined the forum but have not posted in the new members yet because.

I have seen a 2004 tdi auto for sale in a garage.
When i looked at it the yellow oil light was on, He says it's probably a sensor and he will get it done.
Other issue were both front windows not working but thats on the list to be done by the garage along with a new mot.

My concern is the oil light. When i go back to collect the car what should i check, I have taken it for a short test drive and it seems ok but before handing over cash i want a longer drive.

It is a nice looking car but it does have 141k miles but has service history,

Any important things i should check when i go back.
The name is Russ by the way and if i do buy it i will post some details in the right section.