The bigger issue, is Norwegian are having to ground aircraft that are costing them anywhere around $1m a month in lease payments, then wet lease in Wamos and Hifly etc to cover, costhing them lets say another $1m per aircraft per month. SO already $1m an aircraft down every month.
Its all well saying RR wiull cough some compensation at some point, but a) it may not over the additional costs and b) may take years to come in, causing a cash flow issue in between.