I'm the same age, have inherited my home from my parents and am looking to do the same thing myself. I've done a lot of homework and in a couple of months will be ready to start looking at illustrations and quotes. And there has been a fair amount of that 'homework'. I've had some good advice from Key Retirement and also from Age UK.
You have to be honest about the value of the property, about how much you want/need and what you want to do with it - don't be greedy. In any case most lenders will only let you have up to a certain percentage of the value of the property. In my case I want to get the house put into good order - new windows, upgrade heating etc., so that I can go into my retirement without having to worry about that, and so that when I do either go into care or pop my clogs, it will hopefully have a little more value. I've also spoken to my kids and explained what the situation will be when that does happen. Their response was that they have never expected to be left a huge legacy in any case and there are more things to inherit than money.
You've said that you don't have any children/family to leave the house to. In which case, make a will, so that if there is anything left after paying the money back then it can at least go to a favourite charity rather than back into the government's coffers.
And for the suggestion that the OP could either increase or take out a mortgage? You're assuming that, at 55, they are able to afford this or are even able to get one. I know could do neither!
As I've said, nothing wrong with it, but do your homework and take your time.