No but I have! (DX's by my college dont know how official that was but worked with the techniques)
I also managed my GCSE (admittedly at age30) equivalent and to cope with the maths content of Psychology at year one degree level
So if I can help in any way?
Out of interest, mys ds1 / ds2 are being assessed for dyslexia and dyspraxia atm, ds3 has more complex Sn so isnt at the level yet (DS1 also ahs ASD but they can co-exist)
best tip I ever found for me, was to write all the numbers as weords- no idea why it works but I went from an inability to do the most absic maths, to complex psychological stats using that technique