barracker - I agree, I think the letter could be better worded. I think part of the problem here is that there is a certain coyness amongst the screening community about telling women they have had HPV or have cleared HPV.
My understanding is as follows: HPV causes changes to the cells of the cervix, and these are picked up by screening. In most cases, women clear HPV by themselevs, without any issue, and everything goes back to normal. So if you have abnormal cells, but no HPV, you don't need to worry as your cells will be fine. However, in some rare cases, for reasons we don't really understand, a woman struggles to clear the HPV infection. It persists, and it causes more and more changes and these are the cases that can - if left untreated - turn cancerous over time.
In summary, you don't need to worry. You'd cleared the HPV infection, and you are fine!