The programme was a Saturday evening children's show called "Whirligig" with HL (Humphrey Lestocq), Mr Turnip, and Hank the cowboy - one of whose adversaries was Mexican Pete. "Whirligig" alternated with "Saturday Special" which was presented by Peter Butterworth.

You can find further details HERE

There is a previous thread all about those favourite TV programmes, which you should be able to find.