This is a little complex, I'll explain as well as possible and hopefully it will make sense...

We've got a phone line (one of several to this premises) through Spark, with a normal local number tied to it, and it also has 2Degrees  VDSL on it currently. 

We no longer require phone service on this line. 2D support advise us that we can cancel the number/phone service with Spark with no issues to the DSL, which we didn't think really sounded right. 

Spark say if we cancel the phone line with them, we lose the DSL connection on that line too (this does make more sense). Apparently the process we need to go through is to port the phone number to 2D, we can then cancel it with Spark, and 2D should then be able to tweak things to make it a standard Naked DSL setup, but without us losing connection at any point. 

Does that sound right? Anybody been through this before and knows the correct process? Thanks!