Can electrical circuits be added to current fuse box?

it should be fine, if you put the loft on its own ring on a 32amp breaker, it will be enough in my opinion

I would replace the fuse board with a new metal one which is up to regulations. Your electrician may also add an additional new board separately to your old and running a separate circuit just to the loft. Without viewing your job first would enable us to advise fully.

Yes, electrical circuits can be added to a fuse box if certain conditions are met, e.g age of Installation, spare ways available, total current demand will not exceed your main fuse rating e.tc. Some Installations will meet all of these conditions especially if your Installation is Inspected and tested periodically.

If adding new circuits even if have space then these need to be brought into the latest standards

If there is 2 rcd in fues box it is allowed. Its all depends on electrician.

It will need to comply with current regulations so you could have a separate RCD Board for the Loft conversion which means you do not have to change whole fuse board

Yes if there is space left in the fuse board you will know this if there are blanks instead of mcbs or other protective devices in place

You can add them to this board as long as the regulations at the time of installation where met. The whole board will need to be tested and certified if a new circuit is added though, so whilst this is being done it is often not a bad idea to upgrade to the latest specification board.

Ideally since there is space for new circuit in your fuse box it's fine to go ahead with loft wiring. But to comply with the latest edition of the regs you'd need a metal cased consumer unit

I would recommend replacing board. But it’s only an advisory to change( grey area) , so existing could be used