Buying w/partner & BTL'ing our flats

[Mark83]

I thought I'd ask on here for some impartial (and hopefully educated) advice.

My partner and I want to buy a house together. Simple enough if we both sell our flats but wondered if we could keep one/both.

We both have mortgages on our flats and wondering if we could; convert to BTL, take some equity out for a deposit and get a mortgage on a 'family' home.

My flat is worth c.£170k and I have £70k remaining on my mortgage. 1-bed in Ware, Herts. £750pcm rental return.

Ms Mark83's flat is worth £325k and she has about £270k remaining on hers. 1-bed in Kilburn, London. £1300pcm rental return.

Household income c.£100k

Over to PH...