Beautiful girl. My wife had bassets growing up and in her experience with two of hers they developed cancer around 8, they tried to address medically however around 10 is when they passed. I’m sure there will be more posts from teazelsmum and Mikey, they will be able to provide more insight to the life span that they’ve seen in their 30 plus years of experience. I have read on this forum that once you pass the terrible 8s they can go on for a while.
I never had one live to quite that age Richard but mine normally lived into their early teens. The norm used to be around 11 but with better food and veterinary care, most breeds do live for longer than in the past. I always felt that if I got mine through the 8s, they'd live for around 4+ more years. With luck. Very sadly Frankie had to leave me at 10.5. Too young.
I hope you yet have more time with Dollie who looks quite the character.