A 40 lb horizontal mount ( 9 gal ) in USA terms is a bit of an odd-ball. Have you tried all local RV and propane supply stores? Who gave you the broken tube story ? Were the tanks just filled ? Possible overfilled or filled upright , when they should have been filled in the mounted possision. Is the freeze up the same no matter which tank is used for supply ? Sounds odd that both tanks would fail the same way at the same time !
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.