Ensuite room or studio for couple in Brighton and Hove

Please help find a room with a bathroom or studio for a young couple in Brighton and Hove up to £ 750.
She is a student who works and a boy works.
They do not have a guarantor, but they regularly pay for the current accommodation, which is too small for them.
They have preasettled status.
Before Brexit, parents were guarantors, but now most agencies do not accept EU guarantors.
Thanks a lot, worried mom.