Straight steel for making a hole. something like this: Wiggle around getting stones out of the way to about 2 foot down.
https://www.wickes.co.uk/Wickes-Car...gclsrc=aw.ds&dclid=CMafwJX969oCFY4T0wodB1AGxw
And a double handled post knocker like thisplus a mate to help)
https://www.screwfix.com/p/roughnec...gclsrc=aw.ds&dclid=CNP35Kr869oCFcQS0wodGdQAEQ
20 isn't very many to knock in by hand.
Not sure hiring will work out much cheaper, if I take a week to do the work, which I might, I will have nothing later and spent £144.
Sorry but 4" or 100mm are sold as posts. Google says so. A Stake is a small wooden post. FISHGUTS is only right if you are a fit healthy young person that doesn't have a fascination with motors and engines.
Andi.
Hire a mini digger, press posts in with bucket, spend the rest of the day playing in mini digger. Win win!![]()