Hi, if you click on the link here, there is a form to download, and it gives all the info you'll need. I have used this company and will happily recommend them.
Ooh thats good to know as i've sent my clippers to be repaired to simpsons. Was going to wait to see what they were like before sending blades to be sharpened , but think i'll send them straight away after that reccomendation!