I have taught PHP - MySQL for a number of years and the best text book is PHP and MySQL Web Development by Laura Thomson & Luke Welling. It's now in third edition and you have to put up with US spelling, even though it is written by two Australians
, and deals with creating and editing text files using PHP.
There would be nothing wrong with using PHP to edit the file containing the list to remove the radio button in the code. It might be a bit of work but careful planning and the use of variables would avoid having to setup a database to manage this.