No, I'd wager that's a misconception on the part of whoever you got the idea from. I can't really see the likes of Mario Testino (or David Bailey, in his day) getting to their level in the industry by being 'laid back'.

To my mind, if you want the best you have to present your best, and the advice that's been on offer here (whether you like it or not) is in your best innerests and, in the main, sound advice for any work endeavour, not just the model industry - which is, as you know, extremely competitive and riddled with cowboys (who are, generally, laid back).

Anyhoo, I'm inclined to agree with Fen with regards to 'getting it right'. Professionals don't make excuses (no matter how valid) they just get it right.

Dyslexia, or not, when one is trying to make the right (first, second, (if you're lucky) third...) impression you need to make time to 'faff about' with that if you're serious about what you're trying to do (even at this level) - I suspect a poorly written & constructed covering letter to an agency would join the other 99.9% of all such letters in the bin, there are no 'valid excuses', rightly or wrongly you will be judged on that initial contact, and you have to make an impact, the right impact (and that may well be before they even see what you look like).

You may think we're being harsh, but as I said, this is nothing compared to the real world. Just sayin'.