Inside IR35 expenses vs reasonable adjustments for disability

[Lance]

I worked with a guy once who deliberately paid PAYE for moral reasons. He simply thought it was the right thing to do to pay the tax.

I know someone who did that as well.

If this is the OP's position then he could run as outside IR35, deduct expenses, then pay the full remainder as PAYE. I cannot see that HMRC would even try to investigate your IR35 status if you did that as all they'd gain would be tax expenses.