Apologies if posted wrongly but can't find a section specifically fro drain queries. Situation is we have a totally blocked drain carrying water of 1/2 a big roof. The drain has been blocked for a good while by the look of it, (only bought recently and still under renovation). I can only asume this drains into the main sewer as there is a trap just below the gully. The main foul drain lies down the side of the house and has 2 access manholes, every thing here runs perfectly, but these manholes are before wher I suspect the rainwater joins and there is no further manhole to inspect from or rod. So, as the drop fvrom the gully was frost broken due to remaining full constantly I have dug out the gully and trap to expose the clay pipe and get a couple of feet away from the wall to rod it. The problem is the drain is about 1ft deep at this point but then drops through 2 elbows but can't tell exactly which direction it runs and is about 3ft deep I,m guessing. Anyway I can get 7 rods down with ease but come to a dead stop, it actually feels like I,m hitting a stop or change in direction that the rods can,t make. When I broke up the concrete to expose the drain it was obvious that there was 3" of later concrete on top of the original 3. I suspect maybe an access point was concreted over? So can I hire or get someone to stick a sensor or even camera to pinpoint where the drain lies and and which way to go with this. I would sooner go this route then get a builer fried to dig out than put the whole problem with an unknown outfit? Soory for the length of post, but any advise/experience would be greatly appreciated, cheers.