Council refused bond for cottage - need advice

Long story. I had to leave my rented cottage to look after my mother when she came out of hospital. She eventually went into a lovely care home as she had dementia. I had to let her home out to make up her fees. This would have made me homeless had it not been for a friend that offered me a temporary house share. Over a year has gone by and i'm getting strong hints that I should get my own place.
I've found a cottage that has a garden that I can just about afford. I receive ESA Support component and PIP lower disability rate. It has a garden, and i need that as I have mum's dog plus my own.
The council have refused me a bond stating that I should be looking for somewhere around £350. That would be a 3rd floor flat and no garden in this area. The local homeless society PATH would do a voucher but the letting agent doesn't accept them. So I've hit a brick wall. I've saved the rent, my brother has agreed to be guarantor. I have to pay his and my application fee too. Any advice?