re SSDR check out
BMAA SSDR Doc
It's not just max weight 115kg, max empty wing loading 10kg/sq.m as well. I looked at the E111 Eindecker but the wing loading precluded SSDR. Perhaps the biplane models would fit the requirements.
Their "Dream Classic" would be an SSDR possibility.
Originally Posted by TommyOv
...would any engineering types on here care to explain why the designs aren't approved, and what sort of modifications would be required to get them a permit to fly?...
Not an " engineering type" but....designs aren't approved because nobody has gone to the immense amount of work required to get one through the PFA system for unapproved designs. During that process the PFA (soon LAA) will decide what mods are required, if any.