Other crosses of Rhyncholaeliocattleya and Schomburkia are listed as Rhynchomyrmeleya but your particular cross is not registered at the RHS so I guess that leaves it as Rlc 'Lester McDonald' x Mcp tibicinis.
Paul has some of the most interesting crosses of Mcp.
These plants can be quite different from one to the next. Two siblings next to each other may not even look like the same plant.
Rhynchomyrmeleya is abbreviated Rmy
Rmy(Rlc. Lester McDonald x Mcp tibicinis)
should not have apostrophes on the name as it is a registered name not a clonal name. Most people do not put the cross family on the name until it is registered.
Wow, what a coincidence. I was just reading that Paul and Mary Storm will be the speakers at my orchid society meeting this Tuesday (Jan 11). He will be speaking on "Schombo-Love 101" and "The Wonderful World of Schomburgkias and Myrmecophila and their Hybrids". Maybe he will answer that question!