Removing policies specifically designed to victimise the homeless (like the one in the OP) would be an excellent start. As would funding/managing social care properly and using staff who are adequately trained to deal with people who have mental health problems, rather than tearing away their sleeping bags and food parcels by force (which if you support 'making life uncomfortable' for those on the street is indeed what you are supporting). There are plenty such people around, but gutting of council budgets over the last few years has made it difficult to hire them or keep them on. Reinstating some of the mental health trusts that have been unnecessarily closed down over the last eight years would, obviously, be of great help in alleviating a problem that closely dovetails with mental health.
A more difficult problem are those in shelters, which I think pasta described earlier in the thread. 'Difficult' does not mean 'insurmountable' though, and a lot of those problems exist because small charities have largely been left to deal with the problem on their own.
If you're interested in more specific policy details (and have time/inclination to read through a large report on this), there are some excellent suggestions in this report by Crisis:
(Link goes to a PDF, FYI)
https://www.crisis.org.uk/media/238959/everybody_in_how_to_end_homelessness_in_great_britain_2018.pdf