Speaking as someone with a line attenuation of 58db (same as yours), and one who's been stuffed onto a 15db noise margin target in the past, I can say you're likely to get a connection speed around 2-2.3Mbps (should you end up with a 15db margin on ADSLmax).
If you get onto MAX, starting with the default 6db target, you could get up to 3.5-3.8Mbps, but only if your line is very quiet, is underground and doesn't suffer much from nightime noise (e.g. AM radio), otherwise you're likely to get around 2.5-3Mbps.
Ade
Giving UKFSN/Entanet a try
DL Sync 4000kbps
UL Sync 448