Bulk LPG - Cheapest suppliers / supply route?

I am just coming back to these forums after a little absence. But nothing has changed in the meantime. Just like thozza, I have had a price increase after a ‘win back’ fixed price period.
I recently submitted a written statement to the Parliamentary Sub Committee on Energy and Climate Change. They were taking evidence on Energy Prices Profits and Poverty. They are now recommending that the Energy Minister introduces Regulation into the LPG market. You can read their report by Googleing 'energy and climate change subcommittee', look under Committee Publications and find 5th Report - Energy Prices, Profits and Poverty - Volume I and in particular Para 25 of their Recommendations. Please make sure your MP reads it and then seek his/her support by writing to the Energy Minister. (Sorry I am not allowed to post a link)
In one particular battle of price rises, Steve Richardson, an independent consultant was able to help me secure a reduction from 56 pence per litre to 43.5ppl. He can be found by Googleing 'fuelandlpgservices'
I have been digging around following my recent price rise to see how the wholesale market has behaved over the last 12 months or so. Price Indexes are very commercially sensitive although the Office of Fair Trading (my contact has been Bob MacDowall), who are, failing any statutory regulation, the de facto regulator for the Bulk LPG domestic market, tell me that Flogas should advise their customers if asked about the Platts LPG Index. There is another trade index that is comparable to the Platts and I am assured that it shows that the wholesale LPG price FELL by 9% between September 2012 and September 2013.
Keep fighting; I am more confident that I have ever been that the LPG Market will be regulated and retail prices will be published.

We've recently moved into a 3 bed house with LPG central heating (new condensing boiler) that is being supplied by 4 x 47KG calor bottles on an auto change-over system.

We're paying 70.6p per Litre, though the house did come with 4 full bottles of gas...

We thought we'd see how the winter went as we'd naively assumed that the cost of switching to a bulk supply would cost much more than the annual saving (we'll use 2-3000 litres/year). Now we're trying to choose our bulk supplier for the next two years to rush to get a tank installed as we discover the cost to switch (for a ground level tank anyway) would be recouped in less than a year. We've plenty of space for the tank.

Flo Gas (boo!!) are currently offering us the best deal, of £150 to install (in all cases on our pad, and our buried pipe, with us to arrange internal connections), 42.5ppl for the first year fixed, and 48.5ppl for the second year fixed.

Calor quoted £250 installation, 48-50ppl initially, but no fix, and we're open to escalating pricing.

I've tried two independents, waiting to hear back from one, but the other was £500 installation, 41ppl currently or 46ppl fixed for a year.

All have a £15-£16/quarter standing charge.

Heart says independent, head says sign up to flogas for the first two years and then leave for the independent….

Thoughts?