David, as they have found the problem you can probably look forward to a permanent solution. In the meantime you may have to grin and bear it, move out, or contact a sewage disposal company who empty septic tanks. They may be able to suck it up (ugh) and take it away. Don't know the cost but it's around £120 when we have our septic tank emptied. Nowadays you wouldn't be allowed to run surface water into the sewer (ar least that's the case in most areas) and this has to go into soakaways. Hope this is of some help.