BETTY Yates’ son and daughter say they refuse to let their mother’s killer sully her memory.

In a heart-wrenching interview, David Yates and Hazel Costello said they saw the isolation of their mother’s riverside cottage as her protection and never imagined any harm would come to her there.

Although Mrs Yates has been described as “fiesty”, her children do not believe she would have confronted her attacker.

Mr Yates, 51, a delivery driver from Berkshire, said: “I want people to understand just how happy mum was there. There’s nowhere else that she would rather have been.”

He explained his mother had lived alone in the “dream home” she and late husband Ray had designed and built, since his death seven years ago.

He added: “One of the ways that I cope is my parents were there in the cottage for 40-plus years. They were fantastically happy there and this - the assault is a few minutes - not very long in comparison to what they had up until then. I refuse to let that sully my memory of my mum there.”

Mrs Costello, 53, a solicitor from Staffordshire said: “It seems like it was such a savage attack and it’s very difficult to imagine it. I end up trying to put things in boxes so I put all of this in a box so, in terms of remembering all the things that went before, that’s how I cope. I never want my mum’s life defined by this because it’s like a betrayal.”

She added: “We don’t want our mum’s memory lessened by this - we want her to live on as she was.”

When asked how her mother would respond to someone entering the home she loved, Mrs Costello said: “My mum was fundamentally a trusting person so she would not, perhaps, detect that somebody would mean her harm. That would not have been her first instinct but she wasn’t daft.”

She added: “She wasn’t a confrontational person. If someone became confrontational we think she would probably back away and maybe look for assistance. When people describe her as feisty, she wouldn’t have a been a ‘have a go hero’.”

Mrs Costello remembered her mother as a great gardener who, after her husband’s death, single-handedly diverted a stream in her garden.

“I worried about her falling in the garden,” she said, “The isolation that everybody talks about - it was our protection. We didn’t ever think that something like this could happen as it’s so far off the road it’s so private.”

The siblings made a dignified appeal to whoever was responsible, or anyone protecting them, to come forward. “Perhaps if we understood why it happened or what went on we might be able to cope,” said Mrs Costello.

“We just do not understand why this happened. It’s important because we are concerned it might happen to somebody else and it’s frightening at the same time because we understand it may have been somebody she knew which, in itself, is very frightening because we might know this person or a relative of theirs.”

Mr Yates added: “Please come forward. We are, to a certain extent, living in limbo...we need to know, we really do need to know...If somebody can do this it my mum then they might do it to someone else.”