DFG for loft conversion - anybody been in a similar position?

We are currently looking at ways to adapt our house and to make it more suitable for our daughter’s needs. She is autistic, nonverbal and has GDD.

We are in a 3 bedroom house where my husband and I share a bedroom, our daughters share a bedroom and our third bedroom is used as my husband’s office. When our youngest daughter (with complex needs) was 3 months old, my husband changed career and for that he needed an office at home (a quiet space to allow him to work and a space to store the very expensive equipment, away from our young children). My husband is also on call so this office is crucial to allow him to remain in his current occupation.

Obviously we were unaware at the time that our youngest daughter would develop complex needs and the severity. I cannot work due to the severity of my daughter’s needs, making it even more important for my husband to remain in his work.

Our children are 3.5 and 5.5. Our daughter with additional needs wakes up from midnight and sometimes doesn’t settle until 5.30am. This is impacting our 5 year old and as a result (understandably) is affecting her sleep and behaviour

Due to me being unable to work, we cannot afford to move house or even get a room for the garden to convert into an office. Our cupboard under the stairs is too small for an ironing board, let alone a home office or bedroom.

We are looking into applying for a Disabled Facilities Grant for a loft conversion to allow our children to have separate bedrooms and allow more space for our youngest to have safety and sensory equipment in her bedroom.

I’m aware that we have 3 bedrooms, but we are in need of separating our girls so they can have better nights.

I guess my question is has anybody been in a similar position and had it granted, even though we technically have 3 bedrooms? I hope this comes across as intended! Thank you.