Hi @SueSmith,
Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Unfortunately, this is not a service that Bunnings offer, however polycarbonate roofing sheets are fairly easy to cut.
I'd suggest grabbing a pair of Craftright Straight Cut Aviation Snips, which can be used to easily cut through the polycarbonate sheeting.
It's also fairly likely that the team in the timberyard have a pair they could lend you to cut the sheet before transport.
Let me know if you have any other questions that I can assist with.
Jacob
