Alex, Mendelssohn's advertisement (most magazines) states the HM Survivor is Non TSO. Depending on your type of operation it doesn't need to be.
The HM Survivor is actually a Baltic Winner 150, EN 396/EN ISO 12402-6 (
Baltic Lifejackets Sweden | Flytvästar, räddningsvästar, flytkläder, uppblåsbara räddningsvästar). Baltic also manufacture the M.E.D./SOLAS range according to the manual that came with the HM Surv.
Good luck with your choice. I'm happy with mine in the meantime. Proof will be in the testing which of course we always hope never happens, like pressing the ACTIVATE button on your PLB.