it`s all guess work what the problems can be, so once you have had car checked for codes report back

Warning light for what ??. Have you had a code reader on it yet.

Back in the day euro carparts were real cheap but these days they no longer are they want you to use there sister sites carparts 4less and gsf too make it look like your saveing with cheap discount codes
I get 10ltrs of castrol gtx £68 online from a nissan dealer.

Scissors

Scrap yard would be your best bet

Look at oil and see if coolant has got in there then

You'll need to drive for the current tyre pressure to show up. I'd take it back to where you got it fitted. And get them to sort it as its only been on car a few months

Won't come loose with this tape..
https://www.toolstation.com/extra-stron ... ape/p45669

Could be the sensor again was it a nissan one you had fitted ?