Bit of a weird one, the top hose feels like it does have water in it, or at least some. When the hose is squeezed, the reaction of the water in the expansion tank is delayed, as if there is water in the hose (when there's air it's usually pretty instant and direct with the amount of pressure?).
The hose is also relatively slow to return to normal shape after squeezing.

However, I've got some pretty weird action going on with the top hose when I rev the engine:
[ame="http://www.youtube.com/watch?v=1EoGb4t4wPw"]YouTube - MOV00549[/ame]

Could this just be a weak hose collapsing with the pressure of the pump, or would this indicate there's air in there?

could well be a partially blocked rad or just a weak walled hose . does she get hotter than normal ?

Not sure if it gets hotter than usual, the temp sender in the block is mazda and doesn't read right on the RR gauge. Ordered a RR one though so I'll hopefully know what's going on soon temp wise.

Once it's pressurized it doesn't collapse like that but I can't tell if water's flowing or not. At least I know the pump's working I guess.

What's the best way to test to see if the rad's blocked?

don't know about a specific test to see if the rad's blocked, but surely if you take off the top and bottom hoses and run it through with clean water you'll wash out anything that's blocking it?