unlisted exam centre prices cannot disclose before booking exam

Hi all, i am based near barcelona and intend to sit p2 and p3 in june. I have been travelling to uk each time to sit previous exams as there are no exam centres here however after some research acca confirmed that i.could sit my exams in four cities throughout spain. The problem being they are unable to tell me prior to booking the exam what the adfitional cost would be of doing so which they have said includes possible accommodation costs. This seems unfair as i could potentially book the exam in the country i am living in however end up being worse off if the cost turns out to be more than a cheap flight back home. Does anyone have any experience if this and an indicator if this additional.cost payable to the invigilator? Thanks in advance.