Hi!
I agree the softly softly approach might be better at first. WHilst aircrew training we were practising double engine failures. A good look out was made all round then just as the immortal words 'practice double engine failure...go' were uttered, a light aircraft came from our starboard side that we just didn't see. Even though we had all checked everywhere, the combination of light aircraft colour, angle, light (and on) just meant we didn't see him, and I doubt he was expecting several tons of yellow and black death to suddenly plummet in front of his eyes.
There's quite a few of you flying in the Surrey area it seems and there's a bit of a ceiling for those not using Gatwick & heathrow!! This will keep you hemmed in a bit. Why not take your kit with you for the crews to see and explain your massive speed may have made it a little difficult for them to see you!
Perhaps you could offer them some help in the manner of http://www.skywatchcivilairpatrol.org.uk/ or the soon to be constituted Paramotor and UltraLight Search and Record (PULSAR) organisation - watch this space!
Hope these suggestions help harmonise the sky a bit - it must have been something of a scare!
Take care all,
Tj