Adjabuilder Ltd

Bear wall.mix a pva sealer. bonding agent, and primer,
apply to bear wall.
other method.
a wall paper glue will seal bear walls. then apply paint.
bear wall with distress of mortar perished.
bush of surface. apply pva
next time google information first.

Sharp implement at least scrap of paint.
make sure you apply a layer of new putty

You can but it's a dirty way of decorating.
soak old wall paper with sugar soap water
then scrape off

Glazing unit can be replaced.
one would need to measure the glass unit for correct size and depth aswell correct colour insert to panels.
glazing units do break down
gas seal.
first signs are condensation,
if left unchecked condensation turns in to water.
hope this is helpful.

One would have been given a average quote as tradesman would be trying to win the job,
as he knows you could get other quotes.
but.
one would suggest to you to rebuild wall.
rather than repair wall.
advice
one can get as many quotes as you like.
you got a quote for rebuild.
now,
get a quote to repair.
you compare different quote.
you now have a choice.
i myself as a tradesman would go for repair, if i thought wall could be repaired.