In a race to the bottom you could try these:

http://www.ebay.com.au/itm/DC-DC-2-24V-to-2-28V-2A-SX1308-Adjustable-Power-Module-Step-Up-Boost-Converter-/252596426995?hash=item3acfeb98f3:g:w-IAAOSwpLNYBy8f

They have a wide input voltage which for spiky A7 voltage regulation would be good and at less than 1 pound ea. you would have one per circuit. Only 2A max should be OK for LEDs.

LED lights being plastic usually have pos and neg wires so no earthing problems with a floating output.

Location: Rokeby, Victoria, Australia

Have you seen this site?

http://www.dynamoregulatorconversions.com/led-light-boards-shop.php

I may have missed something but can't you just buy or make a lightboard using normal bayonet fitting bulb holders and fit 6v LED bulbs?

Location: Oxfordshire

Thanks for your many replies and emails, I will study carefully the options offered though not electrically knowledgable myself.
It had occurred to me to just use 6 volt LED bulbs or festoons but I imagined the brightness would be less than the multi LED arrays used in a typical modern 12v light.
The 12v lights available here for festoons are thinner in the body than the bulb fittings, and lend themselves to using 6v flashicators. I will ask Peter at CDRC what wattage equivalent his festoons are, AND purchase one of his 6 to 12 converters to experiment with. regard Russell

Location: oz

Squeak, am I correct in thinking that you are only fitting "flashers" at the rear of your Seven? I'm not sure about in the upside down world of Oz , but it would be illegal in the UK as they must be front and rear. Having said that I would recommend a 12 volt conversion using a two brush dynamo and electronic control regulator,that way you can upgrade all the electrics and gain reliability. Whatever route you take good luck.

Location: Piddle Valley

Thanks for that info Peter. I was unaware front was a requirement in UK, I will therefore incorporate front in the plan.
I intend to tour UK later this year in my recent purchase,a 27 Top Hat, and am trying to preassemble the components to fit when I arrive.
My cars here are all LED and 6volt (avatar excepted) See you at Beaulieu!
cheers Russell

Location: oz