USO does not need to be fibre, it may be a 4G or 5G service for example. Also Relish if an area may be able to argue they provide a USO capable service and thus USO clauses don't apply
Yup this is my way of seeing it Relish do give you 30+MB at 3am so meets USO obligations, and there you have it your screwed you could well be left with 3-5mb or relish with it's up and downs, they say it's grim up North, hell you want to try round here.
All1