1. In which country might you eat tin-baw-thee-throat
2. what was the surname of Myrtle, Alf, Veronica and Monty in the programme “That man Chester”
3. what is the English name for those known as Guizers or Guizards in Scotland
2: it was a radio programme and this http://genome.ch.bbc.co.uk/29d706a0227d4337b8ddf51230ca6f07 lists the contributors. I've tried a quick search to see if it came up with any character names played by those actors but without success; maybe you'll have more luck.
2 Dregs
The Dregs Dreadful radio family (Myrtle, Alf, Veronica and Monty) featured in Charlie Chester's 1959 series, That Man Chester. Created by Charles Hart and Bernard Botting.