Wondering if I may possibly have worked it out but again would appreciate any thoughts / comments.

If I fly normally / do circuits, come in to land the Extra flys beautifully and it can fly slowly, it always seems to be at the end of a manoeuvre that it happens where I've had no throttle ie I may be coming straight down towards the ground from height and doing rolls or a Reverse Cuban or Split S. I then give a small amount of elevator to bring it to level flight and then apply the throttle - that's what I'd do with the Acromaster and it was fine and could glide out at quite a speed and go for a reasonable distance without having to open the throttle but with the Extra if you don't apply throttle almost before you start to level out that's when the stall occurs.
Something I'd noticed is the Acromaster propeller stops spinning almost immediately and remains still, it's the same when coming into land, the standard Castle Creations Phoenix 45's factory setting are slow soft brake.
The Extra with the Air Boss ESC I don't think there's any brake set from factory and when it lands with no throttle it's still spinning from the wind until the plane comes to a standstill which would be the same as in the above manoeuvres. I'm wondering if the spinning prop causes drag making the plane slow too quickly at level flight with no power and hence why it's stalling.
I'm sure I saw / had reference to spinning props slowing a plane down in a question about ESC settings.
Again thoughts again appreciated.
N