I paid mine off last year, 6 years from when I set myself the goal to pay it off. It was a 25 year term.
I got myself a mortgage that allowed unlimited overpayments, and that wouldn't change the repayment amount if I overpaid, so this remained the same and I just overpaid (repeatedly!!)
I then found an overpayment calculator on my mortgage company's website, and worked out how much interest would be saved from £100 per month and how much the term would reduce by. By entering higher amounts (£150, £200 etc), I motivated myself to save anything I could. And every spare £1, went on the mortgage. If I sold something on eBay, I paid off £8 of mortgage, every bonus, every spare £20 I had at the end of the month, it all went into the mortgage. I was obsessed!!
Slowly but surely, the balance started to drop and then one day, it was gone. I cried when I phoned the bank to ask doe the final redemption figure, it was a massive massive achievement. I had holes in my underwear, bought my clothes in charity shops because I banned myself from buying anything new for years, meal planned, got a second job for a while, but it was so worth it.
Good luck in your overpaying plans. Every £1 will make a dent in it compared to what was originally planned