series 3 rear seat belts

Hello everyone,
I have just bought a 1982 series 3 88" diesel. It has been serviced but needs work on the chassis and engine (timing chain).
The interior has been re-furbished and bench seats fitted each side in the back but no seat belts.
Do I have to fit seat belts to carry passengers, and if so what sort.
I would be grateful for any advice.
Thanks Bert.

:welcome:

This'll get ya started http://www.landyzone.co.uk/lz/f7/seat-belts-90-side-facing-bench-seats-201184.html