This is a 1970s bungalow.
Not unusually, the flue pipe serving the gas fire and back boiler is of painted asbestos cement. Take care with any repairs and renewals as this is a potentially hazardous material and a Licenced Contractor will have to be used, adding to the cost.
There is also clear evidence of bird nesting above where the flue meets a ventilation tile at roof ridge level.
It is essential to check no nesting material or similar debris is in any way blocking the flue, thus restricting ventilation, as that would create a serious health and safety risk.