I would have thought that falls under permitted development. On looking at it the only thing of concern would be the 50% of the garden rule.
My wife didn't complain when I built my two bay garage with mezzanine, she suggested I put a bed up on the mezzanine and to build a pulley system so my meals could be pulled across.
Sounds to me like you have a great lady thereMy wife didn't complain when I built my two bay garage with mezzanine, she suggested I put a bed up on the mezzanine and to build a pulley system so my meals could be pulled across.
A very nice workspace but be careful when welding in there as that white reflective surface will play havoc with reflected arc. Worst case of arc-eye I ever had was welding in someones garage made of white lightweight blocks. Caught me out and have always been very wary since.