Try Jon Rose at lpgcompare.co.uk who provides a free service.
Here are the deals he got me back in May but I ended up staying with my current supplier Flogas as my tank was not accepted by the companies he got quotes from. Flogas price matched the deals below.
As requested I have found 2 deals, the first is with a supplier called Calor who is offering 33p fixed for 12 months with a 3.5p cap in year 2 and £250 of FREE gas and tank rental is £94 per year.
Calor Gas is a national supplier and considered by many as the market leaders with over 77 years of experience. They have grown from strength to strength helping domestic users of LPG get reliable service with at a good price. Their Head Office is in Warwick and has strategically placed depots around the country to enable them to supply the whole of the UK.
The second is with Avanti Gas who is offering 28p fixed for 12 months with £150 of FREE gas and with a cap of 3p in any 6 month period during the 2nd year and rental is £110 per year.
Avanti Gas is a national supplier who purchased Shell LPG around 5 years ago, since the acquisition they have grown from strength to strength helping domestic users of LPG get reliable service with at a good price. Their Head Office is in Chesterfield and has strategically placed depots to enable them to service the whole of the UK.