Sorry my mistake,the extra usage was 6(cubic metres) on a standard gas tariff. Thanks

Are you sure it was only 6KWh per day extra?? not 6 units ?(either 100s cuft or cu m) -If your extra usage is really only 6KWh then the cost is ~ 20-25p per day.

On timer I'm currently using ~ 7 cu m per day (~ 80 KWh)- with no heating on from 10pm til ~ 5am - in the coldest weather around Xmas with the heating on continuously the usage was ~ 11 cu m per day ( ~124KWh) ie 44KWh more!!

They have a number of different tariffs, so it would depend on which one you are on. You should be able to find this information on your latest bill.

Been trying to work out how much more its costing me to leave my heating on constant as opposed to being on a timer, took readings for 2 x 48 hr periods and found that leaving it on constant it only used 6 Kwh more gas than it being on timed,anyone have any idea of the price of the 6Kwh. Cheers