Mail intercepted and taken

Hi, a colleague earlier this year got married in India and arrived UK on the husbands visa and is having domestic violence issues. She lives with husband and his family in a house.
Recently her dad is visiting and staying at the same house to try and help and create peace and to protect his daughter but it is not working..
She reported to the abuse to the police and then retracted for fear of more suffering at home. But the police sent communication to the address and the husband picked it up as he was not working on that day. So she admitted that she reported the abuse to the police and retracted. Now the husband and his family who are also living at the address, aside abusing her, are keeping an eye out for her mail. What's the best solution to deal with this - any suggestions/help will be greatly appreciated.

She also wants to move out of the house but when she contacted institutions like Women's aid she was told that there are no places available and the shelters are full. What is the best recourse? She is on a minimum wage. Again any ideas/suggestions will be most helpful.

She is also trying to find out if there is any way she can get a visa independent of her husband. Not sure if this is possiible considering that she's been in the country for a little less than a year.

Thank you so much.

Is there anywhere else she can get her mail sent?

Or for contact with agencies such as police request email as the means of communication.

Thank you Wyspecial.
My colleague is very new in this country and has no family or friends here. While browsing online, I have found out that Post Office have a facility where one can opt to collect their mail from a customer service point via a P O Box for a charge of £39.60 for a month, £192 for 6 months, £330 for 12 months. But one must phone the post office to tell them not to send a confirmation to the home address (cannot do this online).
Thanks.