Perhaps the 15 regular flashes indicate that the brake is applied
(or brake switch/wiring fault)?
Are you sure your brake was not applied
(or the brake lever not fully released) before?
As your Hall sensors are definitely working, it sounds to me like either the Phase wires or Hall sensor signal wires are not connected in the correct positions/sequence, and this could explain why the motor is simply stalling instead of trying to turn.
If the controller thinks that the motor's shaft is in a different position due to incorrect wiring, it could be applying a reverse voltage to the phase wires which would cause the stator coils to magnetically attract the closest magnets causing the stall protection to cut in
(hence the four flashes) instead of repelling the magnets, which would force the motor to turn.
The only problem you will encounter with trying to run the motor with no load is that it might rev up to maximum rpm as soon as the throttle starts to work.
This is because the throttle controls the motor's torque
(not its rpm) so until the controller registers some load on the motor's shaft
(by using current sensing to determine the torque) it cannot control the torque.
When load is detected, it should then be able to regulate the motor's rpm by adjusting the amount of torque being produced.
Ok, that last problem of my throttle acting like a break has suddenly been resolved, now it runs seemingly like it supposed too except only it runs backwards (unless I switch it in reverse but then my brake doesnt work?!?)
To reverse the motor's default direction of rotation, the
Blue and
Yellow Phase wires must be swapped over on the controller terminals, and the
Green and
Yellow Hall sensor wires must be swapped on the Hall sensor connector.
The regenerative braking
(and the cruise function) will only work in the forward direction, which is why your brake doesn't work in reverse
(but it should still cut the power to the motor).
Alan 
