Erm, I'm not sure a horse "whisperer" is a sensible route to go down. I would suggest you either seek a BHS reg instructor who offers ground lessons for issues like loading, or look for an IH type instructor. http://www.intelligenthorsemanship.co.uk/
Garry Bosworth is absolutely brilliant. Google him. Trains with Kelly Marx and Monty Roberts, does the Your Horse live shows with them etc. He sorted my old horses loading issues out. Extremely paitent and kind. He's lincolnshire based but travels, charges per mile but is very good so worth the money IMO.