Parts list 

1 x 30K Ohm Resistor
1 x 100 Ohm Resistor
1 x IRL1404Z Mosfet (N)
1 x SPP80P06P Mosfet (P)
1 x 6" length of red 16 AWG wire
2 x 3" lengths of black 16 AWG wire
1 x 3" length of  thin wire for the signal wire
 
Various Heatshrink, I used 2mm, 3.5mm, 10mm and 13mm

                     Tools Required 
 
Soldering iron - keep the heat as low as possible
Solder
Sidecutters or pliers
Heatsink clamps - I use large crocodile clips

 We'll start with the N Mosfet and the 30k resistor

Carefully bend the source pin into a U shape
Cut a length of heatshrink to cover the resistor 

Lay the N mosfet on to of the P one and bend the ends of the N mosfet's gate and drain pins so they can touch the P mosfets legs without strain 

Cover the gate and drain pins on the N mosfet with heatshrink 

Solder 1 length of black wire to the source pin
Solder 30K resistor onto the source and gate pins
Heatshrink the black wire solder point
Heatshrink the whole source pin

Here's the completed N mosfet from another angle

Now we'll prepare the P mosfet

Carefully bend the source pin outwards to allow the wire to run alongside the mosfet

Note the 100 ohm resistor - we'll use that later

Remove a small section on insulation from the middle of the 6" length of red wire
Tin the exposed section
Solder to the source pin on the P mosfet

Heatshrink the joint

Now place the N mosfet on top of the P one and solder both sets of gate and drain pins together

Solder the other 3" length of black wire to the drain pins
Heatshrink the joint

Solder the 100 Ohm resistor to the signal/trigger wire
Solder the other side of the resistor to the gate pins

Heatshrink the joint

Here's the almost finished unit, now's the time to test it
Note - you need to add another bit of signal wire from the other side of the trigger switch and join it to the motor+ red wire. Where you join it will be dictated by what gearbox it's going into

Heatshrink the whole unit.
1 x mosfet trigger switch with active braking........done

All thanks, chocolate, beer etc gratefully accepted