When seats needed to be removed or replaced, there was no automatic right of renewal and the plaque was returned to the family.
Mr Cramond said there would be a lot of sorry people around the area if a 10-year memorial was all they got for their money.
The original seat and plaque was funded by Mr Cramond and his late wife Shirley in 1996. Adding to his distress was that a neighbouring seat and plaque to wife Shirley, installed in 1998, was starting to rot and would also need replacing.
He said Mrs Darragh's seat had become the gathering place of remembrance for her grandchildren and great-grandchildren. "Now there is nothing to remind them that this was their special memorial of a beloved lady. Imagine my consternation when visiting the park last week I discovered the seat and plaque were gone.
"Instead there was a new seat, but no plaque."
Parks manager Mark Smith said he understood it was a difficult issue because 17 years did not seem a long time to memorialise a family member.
Mayor Stuart Crosby intervened in the issue, saying the council should offer a replacement option to the family when a seat needed to be replaced, such as a new seat paid by the family and the plaque remaining.
The council responded by Mr Smith gaining agreement on changing the way it responded to requests for memorial seats. He said the procedures had been updated in order to recognise the significance families placed on memorials. "From this point forward, the council will consider memorial seats as a council asset once they have been installed and for as long as the site remains suitable."
Mr Smith said memorial plaques would go back on replacement seats and Mr Cramond would be offered the chance to add his family's plaque to the new seat.