I listed the job with all the requirements in details. I requested Ahmet to provide the price of job in mybuilder portal.
However, when I called him over mobile, I explicitly asked him to go through all the points mentioned in the job and then get me the price confirmed. Ahmet mentioned that he will be able to complete the job in £80.
When he arrived to carry out the work, he suggested it will be £110. Agreed price £80 was only meant for boiler service and gas safety and not for everything listed in the job.
The job was decided to carry out on Sun,31st Mar as I was moving into my new home on Sat, 6th, April. So I needed to finish the gas safety, boiler and heating before I move in and I was running out of time, so, I agreed to let him continue the job with the new price.
He did carry out job a pretty decently, though.