Is it not the case that the target SNRM has got DLM'ed up to 12dB? Sorry, I've probably missed something from earlier.
I thought about DLM revenge due to plugging/unplugging when Taurit was doing the extension testing, something that has zapped me personally when I've been doing too much mucking about in one day without following the kitz rules. http://forum.kitz.co.uk/index.php/topic,15905.msg307641.html
Whatever, unless I'm way off, if your target SNRM is 12dB will have to wait for ages for DLM to forgive you if it's due to testing-related sin, but if it's a bad line then it's never going to come down until you get the line mended, or internal wiring, interference, filters, modems etc sorted out. Do all testing straight into the master socket with a high quality eg Tandy short cable or even straight into the test socket with no filter and a short good BT-to-modem cable as that rules out all wiring and filters temporarily. Recommend BT faceplate-type filter, and Tandy ultra-short cables to maximise the last drop of performance and give us rule-out.
Absolutely agree with ejs about the peak being too wide for a radio station, and the wrong shape, unless I'm going mad. Guys, what about intermodulation between a radio station and other noise? Would that work? If so that means a non-linear element inline which is easy enough to arrange.
About interleave some ISPs can set interleave on/off/auto on BTw 20CN, but if I remember correctly that's it, there are not different levels. I think I being BTw 21CN get three levels for downstream, off, low and high or something, and I can't remember about auto. I have locked mine on to "on" as opposed to auto, and it's on high or whatever it's called. LLU will presumably be something else.
Burakkucat will be on LLU? So not comparable in some respects.