Just logged in to find a number of PM's about this.
I built it detached by 1" from the main house, as the building control officer told me on the phone (whispered) that detached is detached. 1" is detached. 1 ft is detached. The gap is irrelevant.
I built it all myself, no planning officers or building control involved in the end as it's under the thresholds in height, area and attachment etc. The only help I had was the concrete pour (from a mixer lorry). I'm no expert and I made mistakes, but I had fun, learned some new skills and it's stood strong, secure and weather-tight since 2012.
The real test will be when I come to sell the property and surveyors & solicitors have had a look, but I trade properties for a living and the things I see missed, I expect it'll be fine.
Just in case, I have an appeal case handy for reference, where a building was detached by 25mm, which is attached to this message.
Here are some pics of the build:
There's another thread about the timber-framed building too:
The rubber roofing was well worth the extra money. I'm learning from property refurbishment experience the problems that leaks can cause!
Hope that helps!