Hardy Tropicals UK

Info needed from experience around the UK & Europe - comparing these two palm species on their frost hardiness ?

If you have grown both outside - which one is more tolerant of frost & to what temperature ?
This will help me position them better in the garden.

Thanks,
Rod.

One for Nathan to answer methinks.

Some years ago I did grow a R. Sapida. Kept in a pot and plunged outside in Summer in dappled shade. An early frost of minus 3.5c killed it. Most annoyingly, the frost was not forecasted and came out of nowhere. They have some growing on Tresco, or at least did in the 1990's.

As I said on the EPS forum T. martianus is definitely hardier