Indoor icing up

Hi Guys

This is annoying me

Hitachi wall mounted 7 Kw unit

Called out unit cycling on and off with no faults ,
Turns out unit is cycling off on the indoor coil thermistor, when I take the thermistor out the unit runs but started to iced up badly,

Long story short , leaking flare nut , repaired and recharged system .
HOWEVER
Unit is behaving the same way only running for longer . I’m getting frost on the suction line and if I remove the indoor coil thermistor the unit will run but will eventually ice up.
Coils are clean , charge is ok, however it seems that the LEV is wide open, couldn’t get through to tech to check coil voltages . Would this account for the suction frosting up after a couple of minutes ? What controls the LEV?
One possibility is the heat load , the outdoor is exposed to sunlight all day and with the extreme weather we are having I wonder is the system struggling . ?

LEV could be stuck open, i've had it on their outdoors. Even in this heat valve should control super heat so long as gas charge is correct, sounds like unit is going off on coil freeze protection, might be worth ordering a head and thermistor?