also is possible to apply for permanenent residency at the BHC as we have been married for 5.5 years, or do we have to apply for a settlement visa and then go to the uk and before it expires apply for ILR.
Actually, in a sense, neither of those two alternatives. The application needs to be for a spouse visa but they should issue ILE .... indefinite leave to enter .... the variety of ILR that is issued outside the UK.
However not all British Missions around the world are up to speed on the ILE possibility, although it was introduced as long ago as 01.04.03. So it will do absolutely no harm submitting a covering letter with the application pointing out that you and your wife have lived together outside the UK for over 4 years, and accordingly the visa, when issued, can be ILE rather than a standard 2-year spouse visa.
also as i am abritish citizen can she apply for naturalisation after 3 years of being in the uk; ie 1 year after obtaining ILR and including 2 years spouse visa.
Yes the 3-year rule applies. If ILE issued abroad then there will be no need to apply for ILR in the UK in order to make the Naturalisation application after she has been in the UK for 3 years.
One more query....i have a Hindu marriage certificate not a civil one, is that sufficient for spouse visa?
This is actually quite technical but nevertheless the guiding principle is quite clear. Under the terms of the UK's Foreign Marriages Act 1892 the UK recognises as legally valid any marriage that is considered as a legal marriage in the country where the marriage ceremony took place.
So I don't know the answer to your question, but can ask a specific question back. In the country where the Hindu marriage took place, is the marriage considered to be a legal marriage? If the answer to that is "yes" then the UK recognises it as well, but if the answer is "no" then the UK does not recognise it.
Marriage laws around the world differ considerably. In the UK it is possible to get legally married either in a civil ceremony in a Register Office or other approved place, or alternatively in a Place of Public Worship registered as a place approved for marriages. In either case the same style of marriage certificate will be issued.
My wife and I married in Thailand where a totally different marriage law applies. There a religious ceremony ... of whatever religion, that is unimportant .... is
not a legal marriage ... in the eyes of Thai law and accordingly the UK also, they decline to recognise a "mere" religious marriage ceremony as a legally valid marriage. In order to get legally married in Thailand the couple need to go along to an Amphur ... the Register Office ... and register their marriage. As that is recognised as a legal marriage in Thailand, it is also considered as a legal marriage in the eyes of UK law.
So Amitchar, all you need to do now is consider the marriage laws in the country where your Hindu marriage took place. Over to you.