You should not be using that amount of gas, not even for hot water. I have an Apollo boiler, about 20 years old in a four bed detached house. My average gas spend over the year is only £15 per week and it goes down to about £5.50 per week when it's just heating the water.
From what you say you have not been in your place very long. Did you landlord provide you with a copy of the Gas Safety Check?
By law, a landlord is required to:
ensure gas fittings and flues are maintained in a safe condition. Gas appliances should be serviced in accordance with the manufacturer’s instructions. If these are not available it is recommended that they are serviced annually unless advised otherwise by a CORGI-registered installer;
ensure an annual safety check is carried out on each gas appliance/flue. Before any new lease starts, you must make sure that these checks have been carried out within one year before the start of the lease date, unless the appliances in the property have been installed for less than 12 months, in which case they should be checked within 12 months of their installation date;
If you do not have a copy of the certificate, ask you landlord to provide one. When he does, check the date it was issued; t must be less than 12 months before you moved in. If it is older than that, or he does not provide a copy, the landlord is breaking the law.
You should also find out from the landlord when the boiler was last serviced.
In the meanwhile, what controls do you have over water and room temperature?
For example, do you have a thermostat on the wall? If so what is it set to? Anything above 21C will greatly increase your gas consumption.
Do you have a thermostat on the hot water cylinder (about 15 inches of the ground on the side). It should be set to 60, anything higher will use up gas unnecessarily.
If you are living in private rented accommodation, you may be entitled to a WarmFront Grant for loft and cavity insulation and other energy saving help. It all depends on your financial circumstances. There are details at
Warm Front Grants
Although your landlord has to give his OK for the work to be done, he does
not have to make any contribution towards the cost.