Do I Need Planning Permission.co.uk
Making the most of your Home

We own a 6 bed detached house with separate self contained annex set in about 2 acres.
We sought LDC for a 8m x 19m combined garage, workshop and craft room.
It was refused on the basis it was not incidental to enjoyment of our home, too large and too far away from our house (about 44m - on the same site as an approved existing large timber garage and caravan).
They quoted Emin v SSE and Mid-Sussex District Council [1989] 58 P & CR 416 and we cited Holding v FSD & Thurrock BC (2004) JPL 1405
As a side issue, we directed them to gov.uk LDC guidance “ it is best practice for the LPA to have constructive discussions with applicants and, if it has any concerns, give the applicant the opportunity to amend the application before it is decided. ” but they say they will not revisit the decision.
Views and advice welcomed

You’ll therefore need to reduce the size and bring it closer to the main dwelling.

From experience, there generally isn’t a discussion which relates to LDC applications. They either do or do not meet the PD requirements.