Sounds like roughcast to me. There are two types, dry and wet. Your type sounds like the dry dash, where it is first coated, alllowed to set and then another coat of render applied and whilst it is still wet the stones/chips are thrown on using a special trowel. The type of aggregate and stones...
No the walls would not need to be lined. A profesional plasterer should leave the finished skimmed walls to a standard worthy of just a paint finish. Remember the background for the new plaster must be properly prepared so that it adheres. ie all loose plaster and paper removed, p.v.a glue...
If there is to be alot of moisture in the bathroom then plasterboard is a no no. Building suppliers will advise on the products available.
If you are going ahead with the dot and dab, again ask your building supplier of the type of products to use. The backgroung must be free of any loose...
I have installed a radiator in the loft which is the same level, if not then slightly above the header tank. For the heating to work i must switch it on, so that the pump will pump water to this radiator. But i must bleed it too before it works. When i switch it off then the loft rad drains and...