Are plusnet DNS Hijacking?

[#1]

So I don't use the plusnet DNS since I have a paid for DNS so I can geounlock services.
This morning I was unable to use NOWTV until I changed my DNS to plusnets.
So either:
1) My DNS paid for service is not working (am in email support with them)
2) NOW TV have figured out I am using a paid for DNS
3) Plusnet are DNS Hijacking
When I change my DNS to plusnet NOW TV works, when I change it back to my paid for DNS it doesn't work.
Other services which support my paid for DNS work ok (such as Netflix or Hulu) - so I suspect it is NOW TV specific.
Anyone else having similar problems?
Rick.

[#2]

Turns out it was my DNS service - all is good now, but it would be interesting to know if plusnet do (or will) DNS Hijacking.

[#3]

http://hackercodex.com/guide/how-to-stop-isp-dns-server-hijacking/ May help you determine this