I don't think MGB's used "adapters". The wire wheel hubs are specific to the axles while TR's did use bolt on "adapters".
Unless your MGB somewhere/sometime did get some adapters bolted to its steel wheel axles without screwing up the offset geometry.
Even if it were the latter... I believe that MGB's and TR's are different bolt patterns so if they are adapters bolted to the MGB, they won't fit your TR.