If you asked a bookmaker to give you odds on Prince Charles NOT becoming King Charles on the death of his mother, the odds would be quite long. There would be shorter odds on which of his names he will choose to be known by since there are objections to Charles and he has three others to pick from (Philip, Arthur, George).
The main job of UK politicians is to stop people thinking about UK politics. This is why the LibDems are a nuisance with their nonsense about holding a Referendum on the voting system. It might give people ideas.
Lib Dems or no Lib Dems, there certainly will not be a Referendum on the future of the monarchy. The most decent proposal I have heard suggests that on the death of Queen Elizabeth II - a person who has done an acceptable job as Head of State, though displaying insensitivity on occasions that have mattered (Aberfan, the death of her grandchildren's mother) - that on her death, the throne should be held vacant and a Referendum held asking the UK's citizens whether they wish to continue with an unelected and hereditary head of state. Some have suggested that they should be further asked if they want to see Charles in the job. But this cannot be asked, since if they say "Yes" to the unelected and hereditary they don't get to have a say in who it is. That's logic for you.
So unless you want an elected head of state, you are just going to have to get out there, wave your eco-friendly Made in China flag and cheer for your new King.
It's a bit like the Pope's forthcoming visit. Gordon Brown invited him to make a State visit which actually means that the poor old Queen had to write the invitation on her own notepaper. Since he accepted, she now has to have tea with him. "More tea, Vicar of God?". There's no choice in the matter even though Mr Brown has gone away. I rather suspect that the Queen wouldn't mind a Referendum on whether she should lace the tea with arsenic.