Dyslexia
The promulgation of the idea that a person who has dyslexia should be prevented from holding a PPL is appalling and demonstrates shameful ignorance.
Many who have a difficulty reading and writing are also very successful in life, running multi million pound complex businesses. Others I have taught have had diffilculty in reading questions and identifying answering with regard to the 'Otto Cycle' but just the same have no difficulty in stripping and rebuilding an engine in their classic or rally cars and have taught me much about the workings of an engine.
As to weight and balance calculations and flight planning I wish more did it. In my experience individuals who have the common levels of dyslexia are very capable by hardwork to learn the everyday processes of planning by repitition and are unlikely to forget it later. Take a straw pole of the average club member and note how many can remember how to use the 'whiz wheel' or do a weight and balance. If you do not know the answer already then you will be shocked.
this is my user name, the answer is lots of groundschool and encouragement. The cd's that Oxford produce, by example, I have known to be invaluable. By whopity's response don't expect a sympathetic response from the CAA, just get on with it and expect to give the student that little extra bit of support.