My old house was an e! it was insulated in the roof above the loft bedroom and had double glazing throughout.
If someone had suggested pumping shite into my yorkshire stone walls id have told them where to go. Wouldve improved the epc perhaps but caused no end of damp problems i expect.
I dont think its as straight forward as you think it is.
Substitute Cornish stone walls for Yorkshire and bingo! I've just looked at the EPC for our house, recommending cavity wall insulation - find me a bloody cavity in solid walls then! Double glazed throughout, but we lost on having solid walls (feature of a period property), not having mains gas and using oil, (feature of living rurally), not having a certificate for the insulation (dh did it before EPCs were dreamed of), and me not being willing to rip up the floors in the attic to show what was there.
I had to pay for that crock of shit report to boot!
Having lived in a over insulated home in Belgium, where the house didn't cool down in summer, I prefer to stick on a pair of socks and a fleece if I'm slightly chilly here. Older houses are built to breathe, not be to passive house standards.