To change to cavity doors you will need to remove the wall each side of the doors to accommodate the cavity housing. Normal sliding doors would make a difference but the problem with them is they never stay totally closed and they do become quite noisy and annoying. This problem also applies to double cavity doors. The other option is to use bi-fold doors, they won't intrude into the room as much. Do you really need two doors there at all and is the glass above the doorway necessary? My personal preference would be to fill it all in and just have the one door to the room. You could even re-use one of your doors.

just look up a window manufacture anyone of them will be able to make that and install it and you need a plasterer doesn't anyone use yellow pages anymore ,i know that houzz has suggestions but no one has come forward

I'm concurring with @bigreader, looks like a converted garage. If you do not know where services are, contact the council for information. The cost to make a window into a french door is not expensive. You already have the main cut out with the window, so the french door installers will do the additional brick cut out required. It is the cost of the actual doors which would be the most. Why make that living room into another bedroom? By the plan you have posted you will then have 5 bedrooms, and a small dining and family area, which seem to be thoroughfares. With all the bedrooms along way from the bathroom. maybe look at moving the main bathroom into the bedroom wing. Would the bedroom attached to the living become a living area? Why don't you make the two bedrooms on the left of your plan into a bedroom and ensuite, then you know that there is services because of the kitchen being behind. Can I suggest you should always make an overall plan for the entire home, not just one room.

You could double glaze them. We switched from double French entry doors to a single glass door with sidelight and double glazed it, the reduction in sound travel is very noticeable.