richms: Does the router in the lounge have an ethernet wan port on it? If so just plug that into the ONT and job done.
unless I'm misunderstanding, it sounds like this is the solution.
to the OP: How do you currently connect your router to your garage modem? Ethernet I presume.
If so, just leave the router where it is, unplug the ethernet cable that connects the router and modem at the modem end and plug it directly into the ONT. you do not need to buy anything new (assuming your router is pretty good)


