Original freewheel is a TDC, you might find one, I would go with a Suntour Ultra 6.
Original chain was Renold. If you go with a new freewheel, I sugest a SRAM "7-8" speed, PC-48?

As it has 27" wheels, you have many choices for brakes but not for tires...

Try the Koolstop salmon pads, those and Campagnolo levers should help the braking power and feel.

I have an earlier one, lime green, a time capsule save for the seat & handlebar tape.

Weinmann tubular rims were original till a bit later, then AVA was standard.

A great bike for pulling the kiddie trailer, and it looks good with mudguards too.