Hi Nev,
Yeah I asked this question too, I'm on CP69, due out on 2nd of Jan, because my Invoice was issued in November it had the 17.5% Vat on it, however, I was told for the future invoices I will be charged 15%.
Not sure how that leaves me with the loan, HSBC may simply adjust as fit as I don't think they will just give me the extra saved money, or they might. I'm genunely not sure.
As for drop in fuel prices, well I wouldn't expect a significant drop, if one at all. That's how I'm basing this, think worst case scenario, if anything happens that is better, well it's a bonus!
Hope that helps,
Jim