The OEM Hobbymat one is awful (apologies, but it is) – essentially a cheap ‘drill-press’ vice with a short, wobbly, lifting, jaw, running in an ‘as cast’ slot..
It is possible to modify them by machining the slot and fitting a longer moving jaw but then of course capacity is reduced – I’ll dig mine out later and refresh my memory.
I’d investigate something like the ‘milling slide’ vices that seem to be widely available from a number of suppliers*, but worth checking the footprint/mountings against the work-table & T slots.
*see Warco