No replies to my query but I'll report what I discovered in case it's a help to others. The front of this Maytag dryer comes off easily. Remove two screws (one in each hinge) that hold the hinges to the dryer, then lift the door and hinges up slightly and slide them out of the slots. On the opposite side of the front shroud there are two screws as well. When you remove them you can tip the front shroud out at the top and lift the whole thing up off the tabs at the bottom. Now the gas valve and burner and other components are accessible.

What I discovered after much head scratching and investigating is that sometime during storage an insect had built a nest inside the gas pipe clear up by the gas valve. After running a wire through the pipe and blowing it out with compressed air I had unrestricted gas flow and the dryer worked.

Now, although the dryer fires and lights, the burner doesn't seem to stay on very long. It stays on 15 to 30 seconds then goes off for a minute or so before coming on again. This continues for as long as the dryer is running. Having never owned a gas dryer I don't know if this is normal but after drying a load of clothes for an hour and a half and them coming out still damp I think not.

Some of the other parts that I understand will prevent the dryer from heating properly are the dryer cycling thermostat, the dryer gas valve coils and the flame sensor. My question is: are these components testable with a multimeter and if so, how?