Update:
Did some research on the internet and people described BimmerTool App as doing continuous Clear Fault Memory commands while regen is active. Downloaded App for £13.99 as it works with my existing ELM327 Bluetooth adapter.

Set it up for a forced Regen, which it did, but after a few minutes it fell out of Regen. Dont know why. Re-set it to Regen and this time it did it for approx 20 mins.

My notes on the Regen process are:
1) If there are Regen relevant Fault memory errors, the ECU will block a Regen, no matter how hard you drive.
2) Exhaust temp rises quite quickly to >240°C, so you dont need to drive too hard. Once regen is started, exhaust temp rises to around 600°C and it looks like the ECU tries to regulate it there. Of course if you release the accel pedal, temp drops. Soot value decreases quicker if you can maintain >500°C exhaust temp.
3) Regen started at 60°C water temp. I've seen, BMW documentation saying it starts above 75°C but I guess they've reduced this to make it easier...
4) Regen is independent of car speed. I even did a 3-point turn at one stage and Regen remained active.
5) Regen went inactive a couple of times for no reason. Re-enabled it and it all seemed to work again. Just shows the importance of monitoring systems - without them you're blind.
6) INSTA+ is actually not that good for Forced Regen as it requires power cycles to clear Fault Memory and to set Forced Regen. So how come BimmerTool does both with the car and engine running??? Also I couldnt find a way to monitor the temps as well as the the Regen Active state on Insta+
7) Soot level goes down during the Regen but this is a Simulated value. It will go down to 0 grams for a successful complete regen, but it soon rises after Regen. Mine went back up to around 25g within a few minutes. Out of Regen, the soot value is 'real' albeit a function of DPF differential pressure.
8) After the successful regen, I did a counter pressure test and the idle value was approx 20mBar. A bit high I thought although under the limit, so I repeated the Forced Regen. The 25g of 'real' soot minutes after Regen and the 20mBar at idle didnt change. So concluded this is a function of an aging DPF. My Ash value is suspiciously low at 18g, so I guess one of the previous owners did a new DPF procedure somewhere along the line in a bid to cure a DPF issue....
9) In another forum, someone noted an ECU value for soot production which is around 1mg per second. so 1g in 1000 seconds and the DPF capacity of 60g in 60,000 seconds or 16,6 hours of driving. If the DPF is half full then every 8 hours... kinda makes sense as that is approx 240miles at 30mph. Of course soot values will vary. But it just shows that it doesn't take long for a healthy car to suddenly start posting terminal particle filter messages when something starts to go wrong....

I hope this helps someone... there is a lot of drivel being written about DPF regen and a lot of people pulling their hair out - including me until I worked it out...

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Early 2010 E70 3.5D XDrive Msport