Thanks for the replies.
When my wife arrives I inform the council about her stay with me and they change the council tax to the normal rate (no more discount) after submitting our MC and her NIN. I also inform the pension people and my pension is still for single as she cant recourse to public funds. I hope that everything will be alright when we apply for her ILR.
Is there anyone here who is of the same situation as ours that got their wife's ILR with no problem? I wish to hear from you...
Once again thank you for everyone who spent time to reply on my query.