Virgin IP address has "poor reputation"

[#1]

I frequently post to the PlusNet SMTP server from a virginmedia IP when I'm not at home. Today I get my emails rejected by the server either as spam or as being from an IP with a poor reputation:
Reporting-MTA: dns; plus.net
Final-Recipient: rfc822; xxx.yyy (at) btinternet.com [redacted]
Action: failed
Status: 5.0.0
Remote-MTA: dns; relay.plus.net
Diagnostic-Code: smtp; 535 ...authentication rejected as source IP has a poor reputation
Last-Attempt-Date: Wed, 23 Oct 2013 20:37:57 +0100
I have raised a ticket but am told there is a 37 hour response time which is less than ideal. I have also told Virgin of their poor reputation (Richard Branson will be delighted) and hope they will convince PlusNet of their (or their customers') probity.
Possibly someone from PlusNet reading here could expedite this. The IP range I post from is 86.3.222.xxx

[#2]

@Intrinsic
Sorry for the delayed reply, we've passed this on to our networks to team to see if there's any merit in resetting the reputation of that IP. I'd advise not to expect a response until early next week though to be honest.
With that in mind do you know how likely it is that your IP might change?
I ask as if we alter the reputation then your IP could then pass on to another Virgin customer who would then have the same issue.