I know & have dealt with Marc in the past, sadly I do know of his health problems. ( I keep in touch with his show helper 'Alan' )
The reason Marc can not read the letter & no one is around to help is because he has alzheimer's or dementia - I can't remember which sorry. ( This will play in to effect with the response people get )
Unfortunate like few people I have lost an order now for few bits, I doubt I will ever see.
Good luck if you do take him to small claims