Can you help me? Name this sitcom.

Hi, I am Roberto from New Zealand, sometime in the 70's a UK Sitcom played on our only Television station at the time, the Synopsis was....
A single mother with a child at secondary school (around the age of 15 he was a bit of a handfull), one of her neighbours was an elderly man (famous english comedian, possibly music-hall star) who was enlisted by the mother to help look after the young fella after school and they built a friendship.

For the life of me I can not remember the names of any of the actors or the title of the show, I would love to see this again.

Perhaps you're thinking of Spring & Autumn?

https://www.comedy.co.uk/shop/?search=Spring+%26+Autumn