Yes, I heard of them, they'll come to complete a report for the insurer, basically the insurer asks for 3 things from them, 1/ What the fault is, 2/ What the cause was and 3/ Make a recommendation on how to put it right
Don't tell them it was an on going issue, it happened in March and you tried reporting it to the installer immediately without success, once you found they'd ceased trading you then informed the insurer hence the timeline
If it's something they can repair on the first visit they will, they'll have the authority for mainly adjustments but any parts required will need to be ordered and another visit booked, or if they think in their judgement they'll be on going trouble with them they'll probably write them off and replace them, you'll be ok with remco, where are you based?