Here is the grave register at Saltwell, there is no indication of any burial of ashes in the plot in which Robert is interred
https://www.familysearch.org/ark:/61903/3:1:3QHV-P3VC-C946-R?i=743&cat=825084
I agree with Rosie that your first move should be to purchase the full record from Deceased Online. Once you know exactly where the cremation took place you can enquire there for possible further details.
If you visit Saltwell again Robert is interred in section 6 plot number 6179. Staff at the Cemetery office might well be able to advise you of the exact position of the grave.
Many thanks Jen, Tickettyboo has located her, she was cremated at Altrincham cemetery and she appears in the book of rememberence there. Whether her ashes were returned to the NE for family we will never know.
Thank you for advising me of Robert's section and grave number and also that he is buried with his son (from a previous marriage). Over 10 years ago i enquired regarding my G.Grandparents who were buried there. Nothing was online and it was going to cost me 30 pounds per enquiry for them to give me details. I decided to wander around instead and after establishing the area where they would have been buried I walked all around the area (sections 1-5). After about 3 hours and with a dozen gravestones left to read i looked at one and couldn't believe my eyes, found them and their eldest daughter all in one grave. Talk about making my day!!! From memory I know where section 6 is so next time in the UK that is a must visit. Many thanks, I appreciate your assistance. Paul