Is it a mortgage I need?

Adolfine

I am in a strange but potentially fortunate position.  I have bought a small house which requires some renovation, I had planned to sell my flat in London to pay for this, however two things have got in the way - COVID and then the possibility of subsidence.  I am lucky in that my mother has left me a property in London (the flat above my flat and the top flat in the same house) so I am asset rich but cash poor.  

I already have a small mortgage on my flat (£50,000 interest-only which will need repaying in 2 years time).  
My flat is rented out and brings in £1700 per month - this is my only income.
Each flat is worth £500,000 plus.
I am 61 years old.
The flats are in central London.

The insurers are dealing with the subsidence claim at the moment, but added to the mix is the fact that I didn't see a clause in the buildings insurance which required me to have arboreal surveys done each year - so I may have to pay for the work needed to rectify the subsidence.  

My question is, would I be able to remortgage one of the flats and get a mortgage for say £150,000 which I would use to finish the property I have bought and pay for the work needed (if I am liable).  

Hibiscouscous

I’m in a similar position. Watching.

MWT

You need to talk to a broker, but just so it is clear, you already have a buy-to-let mortgage on your original flat which you have let, or was it a residential mortgage with a waiver given to let?

Your new house has no mortgage and was presumably a cash purchase?

I'm struggling to see how you'd meet the affordability criteria if your only income is the rental, do you have the option to let one of the other flats to help justify the mortgage?