Dyslexic son: low spelling age

[bestbefore]

Just after any pointers anyone has to try and help my son. He is 11 and in year 7 - he has just had a report home from school to say whilst his reading age is 11, his spelling age is just over 8. He is a diagnosed dyslexic and his CAT scores are average but I'd like to help him improve his spelling.
Any ideas? He does get Bs and Ds the wrong way round and has had loads of help with that but it persists!
TIA

Apple and pears - though it does take time to get through - so about 20 minutes at least three times a week. Take placement tests to see where to start. It is very good.

Took about two years to get entirely through for mine though we aimed for some most days - then followed with Spelfabet this had Australian pronunciations - but my children weren't fazed by that.

I think somewhere Spelfabet she also has lists of the resources that she's looked at and would recommend.

It's best to do a written program as spelling apparently has a sort of muscles memory element to it - but if time wise that isn't possible Nessy exists and my Dc primary school recommend it though it's had a mixed response from my children.

Not sure how to help with the letter reversal.

thank you - will have a look

We have a specialist tutor for dd2. We did receive funding for this but it has just finished. Will manage but it's ££££ I firmly believe she still wouldn't be able to read if it wasn't for her tutor. She literally could not read at all in year 5. Spelling isn't brilliant but she gets by. The school are excellent. She has an alpha smart typing tool as her writing is illegible and too slow. Other than that she does amazingly well at school. Year 8 and working at GCSE level.

We've also done a lot of support of reading and handwriting - more fluid handwriting does seem to ease spelling at least for our older two children.

Speed Up is a good book for older child deals with handwriting fluidty - but won't deal specifically with swapping D and B round.

I meant fluent and fluently above .