Mr Zahid
I recently moved from canada to Qatar, I also did the shipping of a 20ft container. you have to get a clearing agent once you reach Doha. or there are other options as well, from your shipping company, you can request for door to door service including unpacking but sometimes the quotes are much higher. I will suggest that you should book the shipping from your door to port area here in Qatar. Your shipment will take a while to reach here better to check with shipping companies in UK.
Once here, you can contact different agencies. You will need a letter from your employer and any good clearing agent will charge around 3500 Riyals to clear all the stuff including transportation and light assembly. I did mine with Tokyo freight, they are pretty good.