You may well be correct about Tessie being Teresa or Jessie - I have just been working from a list my Mother wrote out some time ago where she showed Tessie as Mrs Edwards.
Heather Crescent definitely rings a bell - I'm sure my father lived in Pulrose at some time in his youth, and I can remember Uncle Dick (Richard) living there (and drinking in the Quarterbridge pub !).
I grew up in Willaston.
What is your connection to the Cowins ?
Andy
PS also e-mailed you