Be proactive while waiting for a connection:
Sligo telephone book:
There is a Ryan-Jones as a hyphenated name, this is quite unusual so perhaps a family tradition
There are 8 Chambers in the Sligo telephone book; 2 Lambe's in the telephone, 1 male and 1 female, Kilgass & Dromahair
These might be worth writing to as well as the Ryan-Jones looking for your Sheila Chambers. Sheila
was not one of the names of the 8 Chamber's listed: If you have a place name that matches one of these would give you someone to write too, but 8 aren't a lot either.
All the address given will be sufficient for mail delivery, no postal codes required..