David, thanks, I meant to post the Inmarsat C NCS freqs within the thread for convenience:
1537.1000MHz, NCS, ALPHASAT (4AF4), LES 344, Region IOR (EMEA)
1541.4500MHz, NCS, Inmarsat 3F5, LES 144, Region AOR-E
1537.7000MHz, NCS, Inmarsat 4F3, LES 044, Region AOR-W (AMER)
1541.4500MHz, NCS, Inmarsat 4F1, LES 244, Region POR
with the active satellite info but obviously messed up whilst cutting & pasting a 'long' post on my smartphone :(
Another indoor antenna option would be to take one from an old 'Worldspace' radio. Maybe find something like that at a a car boot sale / garage sale though they weren't very common.