After receiving advice on this forum I did my own "letter before action" on my headed paper instead of a Thomas Higgins type solicitor, with a made-up form attached setting out the next steps if unpaid.
The debt was only £20 for two cleans on a £10 house and I stopped cleaning in January as reminder for clean ignored. I knocked and put reminders through when I was cleaning in the road in February and April. I believe custy was hiding on at least one occasion.
I put the LBA through on 24th May and gave 7 days to respond.
Yesterday I set up a moneyclaim online account with all the details and was ready to hit pay and send when Mrs Gold said I should give custy a week past the 7 days "in case they were on holiday" and to be reasonable.
So I decided to activate on 3rd June if I hadn't been paid.
Cheque arrived today.
RESULT! (If it doesn't bounce!

)
Note: Get your custies first and last names as MCOL asks for this when filling out the claim. Fortunately I had both in this case.