I'm sure this question has been asked before, but I can't seem to find it, so apologies for duplication if this topic already exists.
I got my UK citizenship certificate on 27th April 2013, and now have a UK Passport as valid from 16th May 2013. Previous to this, I have a valid Indian passport with ILR.
Now, I want to travel to India for a a short time, from 19th July - 22nd July, and I was wondering if I can still use my Indian passport to do that, or will I have to get an Indian visa? I understand that technically I am no longer an Indian citizen, so technically my Indian passport shouldn't be valid, but the consulate website losely states there is some sort of 90 day "grace period", and my understanding is that I should be able to travel during those 90 days on my Indian passport.
I want to apply for the OCI card as well, and I'm hoping to do so when I get back from India. If I do travel on my Indian passport, will it be illegal, or will there be a problem in getting the OCI at a future date? I'm just trying to avoid the hassle and visa fee for an Indian visa

Thanks in advance