I was unaware the trains reverse at Glossop to get to Hadfeild my bad.
Your idea sounds like it would solve the issue. In this
video here at the 25:13 mark the Hadfield platform is seen being used, and there is no curve so 4 car services could work if trains turned around at Hadfield.
The video is from 2017, but I can't see anything having changed in terms of the platform since then.
Edit:The Glossop platform at Dinting would still be an issue, as any service from Glossop to Piccadilly would use the curved Glossop platform.