Pebble dash come of wall and damp on inside wall

Often the pebble dash comes off because it cracked and water got behind it . This will cause an interior dampness within a year . Freezing temperatures will finally push off the loose pebble dash, more rainwater will penetrate the remaining edges and the problem will grow in size .

insufficient information, how old is the house, is it got a cavity or is is solid brick, does it have cavity wall insulation, what condition is the roof and guttering in, is the render loose on other sections of the walls, these are some of the questions you need to answer to be able to answer why you're getting damp, only a site visit could answer these post your job on the site and get a local expert round to assess the cause/cure. good luck Alex

Most probably a pointing issue under the render repoint and repatch to be sure 👍

Yes take the pebble dash off first and let it breathe then take it from there!!!