@FerryMan69 ok thanks for that will look forward to having a go at this
Well the stress test worked well. I was running the strobe from an 80mAh single cell lipo with a flash pattern of 2 quick flashes, a short pause and then repeat the cycle. For those who want the detail … is a 50 millisecond flash, 200 millisecond delay, 50 millisecond flash, 1000 millisecond delay, then repeat. I got about an hour with both the white and red 3W LED’s. I guess I could increase the battery life by having shorter pulses, which I think may be worth a try as the 50 millisecond flash actually seemed quite long. That’s the beauty of using a micro-controller to control the flash sequence… you can easily program it to do what ever you want!
Although the MK2 package is small (about 6g including the lipo) it may be possible to shave off a gram (maybe 2) off with a few component tweaks in the future - just need to spend a bit of time to get a smd micro-controller and a smaller transistor; in place of the 1.6g beast I am using at the moment, which is overkill!
Just found a more suitable transistor… 0.008g; that’s a 1.5g saving already! 
Its also a lot smaller at 2.9 x 1.3mm.
I have just bought what I thought were cheap lights from eBay, Two pairs for £9.74 including tracked post. They arrived boxed, in padded envelopes two days after being ordered.
Advertised as [XPE-R3 LED Night Light Flight Searching Aluminum Head Lamp for DJI Mavic Air #UK This is the link Turned out to be PGYTECH lights which retail for £29
He’s realised his mistake, just looked at his listing and they are now up to £6.99 a pair which still seems a silly low price!