How Much Will I Be Billed For Calling 0844 200 50 50

[#1]

Hi All,
I have the Plusnet Anytime telephone service and need to make calls to this telephone number 0844 200 50 50
I would like to know how Plusnet will bill me per-minute to call that number.  Plusnet say they cannot tell me.
I don't understand why Plusnet cannot tell me how much the call is going to cost per-minute when it is Plusnet that will be billing me for calling it.
The number is for a company that claims to offer cheap calls to Thailand mobiles amongst other places.  On the company's site they say the cost of the call is ¹/₂p per-minute.
I do not believe that I could possibly call a Thai mobile for ¹/₂p per-minute so I am thinking that the true cost of the call may be the cost of calling 0844 200 50 50 plus ¹/₂p per-minute.
If it helps, this is the only information I can find:- http://www.dialaround.co.uk/rates.php#t
I have been unable to get a reply from any other source about the cost of these calls.
Please can anyone tell me why Plusnet are unable to advise me the cost of calling that number?
Thank you,
Chris.

[#2]

It may well be half a pence per minute, plus the connection charge.
We use these numbers to call Spain and the US and that is all we are charged.
Have a look at moneysavingexper.com they have a call checker for such numbers and if it says half a pence per minute that's what it will cost, plus the six or eight pence connection charge.

[#3]

To find call charges check the BT tariff document to find out the"type of call".
http://www.productsandservices.bt.com/consumer/consumerProducts/pdf/SpecialisedNos.pdf
0844 200 is g22.
Then check the Plusnet tariff document to find the cost of a g22 call.
http://www.plus.net/residential/tariffs/homephone.html
Calls to g22 cost 0.5p per minute plus a 9.3p set-up fee.

[#4]

Thank you to all that replied to my question.  The answers are clear and have come as a very pleasant surprise.
Very best wishes to you all,
Chris