Ruth Dickie lives next door at number 6. The 14 sq m visitor centre, at 3m tall, would stand against her garden fence and rise almost a metre above it.
She said she had felt “sick” since the plans were announced, and was considering leaving the house she shared with her husband Jim, who died two years ago.
“He had Parkinson’s and dementia so this was a safe place for him. The garden here was our solace. I pottered while he sat,” she said.
HOLT said the centre was in line with other garden buildings nearby and designed “explicitly to reduce our impact on nearby properties”.
It added: “By ensuring that visitors are kept on site, briefed within an enclosed building, and spend a limited amount of time within the garden, we will all act to reduce both visual and auditory impact for our neighbours.”