Probably either sun or wind damage, they do like a sheltered spot. You could move them if they are in pots .Otherwise there's always next years new leaves to look forward to. Welcome... I am new here too.

Those leaves will wither and die but be patient it will recover and produce new leaves.As previously stated keep sheltered and in the shade.Every leaf on mine went but now 6/8 weeks on it boasts lovely green leaves.

You are lucky Ian. Mine didn't recover and I learned the hard way about it needing shade and shelter from wind! I will stick to admiring them in other peoples gardens form now on.