Thanks. The house had a DPC in 1992, the installer has since gone out
of business. the main walls affected are internal or on the party wall
with the neighbour. doing the outisde may also be tricky because the
wall contrcution is stone dressed brick.

presumably the new dpc would need to go abpve the concret e floor but
below the suspended timber floor? also, is it best to avoid the bricks
that have already been injected?