Hi Freddo
My answer for 79 ends in a T for the second word and you need to think of another word for electricity followed by another word for bill to give what most people have for paying bills etc.
I think 84 starts with a T and is a form of transport that gets you from a to b on rails.
The start of 87 is 5 letters and something lots of people have delivered each day, followed by 6 letters meaning pressure. Don’t think these are used nowadays in offices.
I would welcome help with No 1 as have 2 possible answers neither of which I am sure about.