Chop both types of chocolate into small pieces or use chocolate buttons made for melting.
Put the chocolate into a heavy-based pan to melt with the butter and honey over a gentle heat. Or use a Bain-marie (a bowl over a pot of boiling water) to melt the chocolate.
Toast the walnuts in a dry saucepan and let them cool. Put the walnuts into a freezer bag and smash them with a rolling pin so you get different-sized nut pieces.
Take the chocolate off the heat, add the Rice Krispies, nuts, whole glacé cherries and mini-marshmallows.
Turn carefully to coat everything with the chocolate mixture.
Line a 9 1/4 x 12 inch cookie tray with tin foil. Spread the fudge mixture on the tray, smoothing the top as best you can.
Refrigerate the fudge until it is firm enough to cut, which will take about 3 hours. Then take the set block of rocky road out of the foil tray ready to cut. Cut into equal squares.
The fudge can be stored in an airtight container in a cool place for up to 1 week.
You can freeze the fudge for up to a month.