Naive consent to let assumed but then refused

Both myself and my partner decided the time was right to move in together in the summer, the decision was made that we would move into my property as it is in a more desirable area and fits into our plans for the future.

She decided, instead of selling, to rent the property out, and keep it as a nest egg for retirement.

She contacted her mortgage company to enquire about consent to let, they advised once she had decided whether to rent or not, that she was required to put in writing a formal consent to let application.

We contacted a letting agent, and within 4 weeks of starting the ball rolling, we had a tenant.

She composed the letter and thought nothing more, no reply so assumed all was ok.

Move forward 6 months and she was aware her fixed rate product was due for renewal, she contacted the mortgage company to enquire about products and to confirm that consent to let was applied and if that would affect the product rate etc.

She was told that no consent to let had been given as using a previous valuation, there was not 20% equity in the property. (Non of this was mentioned previous). My partner got worried and told them we did NOT have a tenant, but would be doing so in the near future.

We challenged this change of tune, but did not want to rock the apple cart too much as it may cause us problems.

Next we looked into a consumer buy to let mortgages, however, with the lack of equity combined with earnings of sub £25k a year, there isn’t a suitable product.

The property has a rental income of £500 a month, and now she is on the SVR the repayment is still only £340, so it is making a good profit.

We want to make it all legitimate but feel that the door is being closed at every turn!

We admit we where naive for not looking into this before hand.. any advice would be Truly gratefully received.