Does anyone know if there is a tool you can buy, in a kit to crimp on ferrules for handbrake cables?

Chris

e-Bay is your friend

They also stock the ferrules to crimp on the cables.

What about eyelets.to fit onto the sierra handbrake?

Go to your local yacht chandlers they will do it for half the price of the tools

£10 locally, cut to size and proper grimped end.