Barton - WAL-IOM
Why not fly direct to WAL then IOM.
If LPL is busy they will route you around their zone, pick up the radial for WAL, climb once beyond WAL dme 8d, and ask LPL for a FIS. At approx half way, contact IOM (and use IOM VOR at the same time).
It's a doddle. It's also a super flight.
Point of advice, call up Manx Flyers before you leave, and tell them you are visiting.
Once landed, tell IOM ATC that you don't want the terminal, you want the Manx Flyers - much cheaper. They have a nice club house on the beach also.