As per the title I decided I'd try and see what the difference was between the stock globes and LED's and as it turns out it's rather chalk and cheese...
2X CANBUS T10 12V W5W 7020 COOL WHITE LED CAR TAIL SIDE LIGHTS TURN PARK BULB | eBayThis will hopefully make the ass end a bit more noticeable especially in poor visibility conditions.
Also while I'm here, (as a PSA) after installing both LED's, neither of them worked...great
Turns out they're polarity sensitive and that I'd installed them both incorrectly and after turning them both 180° they were both good to go...phew
Forgot to add that I've got reversing light replacements on the way as well, which should make a difference for reversing camera picture quality in low light situations.