Hi
There is a curry restaurant very near Kings Cross and S. Pancras stations called Kings Cross Tandoori. Unfortunately, I have never been to it and cannot vouch for its quality.
As a Bradford lad by birth, I am used to curries of a Pakistani, rather than Bangladeshi, origin - most of the 'Indian' restaurants in London are run by people of Bangladeshi origin. Nothing wrong with that, of course, but it's essentially a different product to what I'm used to.
I have no idea how long you have to spend in London, but if you have the time, I'd suggest heading east. Forget Brick Lane...I've never been anything other than massively disappointed every time I've visited - and have visited at least ten times.
There are three places I'd recommend.
Tayaab's (nearest tube: Whitechapel)
Lahore - a bit of a pain to get to on public transport -nearish Limehouse DLR (Northen line to Bank, change for DLR, then a reasonable walk)
Zaza's (nearest tube: Whitechapel)
There's no clear winner out of the three - grilled meats (Kebabs,wings, chops) are excellent at Tayaab's with curries arguably sub-par. The opposite's true at Lahore. My personal favourite is Zaza's - also apparently the favourite of controversial Mayor of Tower Hamlets Lutfur Rahman - for the closest approximation of a "Bradford Curry" I've found London-wise.
None of these restaurants serve alcohol. Tayaab's and Lahore both let you bring your own (and off-licences are nearby them both). I don't know whether Zaza's does or not - every time I've been there I've settled for their excellent mango lassi and never bothered to ask if we could bring booze.
To get to the east end via the Hammersmith & City line you're looking at north of 30 minutes each way from King's Cross, but well worth it if you have the time, in my opinion.
Cheers!