Can alternate providers still be used? 1899, 18185, etc...

[#1]

I'm on the verge of switching to Plusnet for my home phone (currently on a combo of Talk Talk and BT).  At present I use the likes of 1899 and 18185 to get cheaper mobile and international calls.  Can these still be used on Plusnet, or are they blocked?

[#2]

Hi there,
The services you mention are not blocked by us, or prohibited in our T+C's. As such they should work fine.
Unfortunately we would not be able to offer any support should these services not work, and you would have to contact the 3rd party provider directly.

[#3]

Thanks for the quick reply - I'll get switched!

[#4]

That's good to know. Can't beat 1899 for daytime calls.