Has the mortgage market changed enough?

Morning all :j

i recently separated with my husband and bought out his share of the property via a separation agreement in writing, also have all the child maintenance sorted etc. The mortgage is still in joint names, i tried to get a mortgage in just my name but no lender would lend, despite the fact i have mainly paid the mortgage myself for the last few years;- the details are;-
earnings 37k net plus 5k annual bonus
house value 220k
mortgage o/s 175k
credit repayments £120 pcm
currently paying £1020 pcm on lenders variable rate but could pay £850 on a more competitive rate.
i have an excellent credit rating, no defaults or missed/late payments for 20 years.
i have tried both L&C brokers and both my current account banks but still no joy.
Disposable income after mortgage, utilities, ctax, childcare, credit payments etc leaves over £600 pcm for food (approx £100 pcm) and car running costs (approx £50 pcm as work locally), i even manage to save £200 pcm into my rainy day account which has 2k in it, with my main current account provider.
I have also just taken in a lodger paying £350 pcm plus ctax.

So why can i not get a mortgage?!?

If i were to reapply now could i use the lodger money as additional income?

any advice gratefully received :D