Anybody able to help me with this? ...pretty please

I have supplied Realex with these URLs:
Callback URL: http://www.anglerscorner.co.uk/before_process.php
Landing URL: https://www.anglerscorner.co.uk/inde...eckout_success

Which I believe are correct...

Still getting a session timeout upon return. I am trying to get Realex to help me but their support has been pretty slow and not very helpful so far.
At this rate we may have to abandon this payment method and go back to our old provider.

I have installed all the files carefully and correctly and given the URLs above, as far as I am aware everything looks correct.
If there is anything that stands out as incorrect or if somebody has any thoughts why I am getting a session timeout upon return could you please let me know.

Thanks in advance