This statement...
All storage heaters made from 1974 onwards have been asbestos free.
From this site...
http://www.storageheaters.com/storage-heaters-asbestos.htm
Seems to answer your question...
I used a search engine using the search phrase
Creda Asbestos
The first result listed the models that do contain asbestos
TI Creda
7001 (SR)7002 (SR)70001 (SR)70041/ 51 (SR)70052/ 61 (SR) Pre June 1975 production of the following models; 72041/ 51/ 61 (SR) 70101/ 70111 (SR) 70131/ 70132 (SR)
70141/ 70142 (SR)
Creda
377 or 'E' Range (SR)
Good Luck...
March 2017