If possible I would try to run a long Ethernet cable from your loft to the studio. It may be possible to use a homeplug / wireless extender but ideally they should be on the same circuit. I would give it a try asap - they are not too expensive. Maybe someone will suggest some way of having an "aerial" outside the studio that somehow could get the signal in, but I don't know if that is possible.
HTC U12 Plus review: Hands-on