Problems getting BTL mortgage. 15 BTL mortgages but no other income

Property Investment

I have a portfolio of 15 properties with BTL mortgages and have a good credit score. Most recent mortgages are with The Mortgage Works who have refused my most recent application to borrow £45,000 on a £60,000 property with rental income from day 1 of £490. My portfolio is worth approx £1m and I have approx £800,000 borrowing. Despite already having 9 mortgages with them they have now decided my exposure is too high - despite having a health cash flow in terms of return against the investment. My yield is approx 5%.

I do not have any other source of income as this is my main work. My husband is employed but traditionally I have borrowed in just my name.

I am trying Birmingham Midshires next week but my broker thinks my options are limited due to the lack of other income. I also have mortgages with Paragon but they wouldn;t consider me on my most recent enquiry.

Can anyone offer me any advice/suggest any other lenders? Much appreciated.