A landlord has a legal obilgation to ensure that all applicances are safe. With regards to a gas boiler they must have that annually reviewed and MUST supply the tenant with a gas safety certificate within 28 days of that service. Also, only qualified engineers are allowed to work on a boiler and it is an offence for any non qualified person to even remove the cover let alone tamper with the boiler. I would formally write to your landlord stating your concerns and request that it is dealt with properly and within a reasonable time. The defination of "reasonable time" is left open to interpretation but I would suggest within the month. Unlike tenants of mine who would phone me at midnight and demanded I sorted it out things immediately.
Sounds like the type of landlord that is unaware of his legal obilgations. Have you given him a deposit
, if you have I would make an educated guess that he hasn't put it in one of the deposit schemes that he has too and is therefore liable to a 3x the deposit sum fine, if you chose to take him to court. NB: He should have given you proof that the money has deposited the money in one of the schemes.
Naturally, if you do decided to take any action it may effect your ongoing relationship with your landlord and you may find he increases rent, NB: that he has to give you one months notice via a section 13 form, or alternatively he may serve notice on you to leave, NB: this has to be a minimum of two months if in a periodic tenancy or longer if during a fixed AST term. Naturally if he serves you notice and you don't leave he would then have to go to court and may employ bailiffs to remove you. This would add another further two months before you would leave.
An important note is never withhold any due payments of rent as this really does effect your legal position and your rights.
acidmouse re: cost, good luck with getting somebody to do it for £1k. £1.5k @ least and I was quoted that over 3 years ago. Quotes are more likely to be £2k plus.