Clause 19.1 is only the PM's obligation to issue an instruction, so if this has been removed but not clause 60.1(19), as @Tiplady says the Contractor still has a right to a compensation event.
This said, for contracts that have either been entered into after the COVID-19 outbreak it would be much harder for a Contractor to demonstrate that the event had such a small chance of occurring it would have been unreasonable for it to have allowed for it,. Therefore the risk may well now sit with the Contractor and should be priced accordingly, this said I can forsee many disputes about this in the future. It would be better for both Parties to use a Z clause to clarify the position in respect of COVID-19.
This said, for contracts that have either been entered into after the COVID-19 outbreak it would be much harder for a Contractor to demonstrate that the event had such a small chance of occurring it would have been unreasonable for it to have allowed for it,. Therefore the risk may well now sit with the Contractor and should be priced accordingly, this said I can forsee many disputes about this in the future. It would be better for both Parties to use a Z clause to clarify the position in respect of COVID-19.