Tenant in industrial unit not paying rent

[gareth h]

I have 50% of an industrial unit in my pension fund (my company occupied it until I sold the business), it is managed by CBRE, who have never been very effective at collecting rent, which normally falls to me.
Since COVID the tenant has said he is struggling to make payments, and I sympathise, however I am at a loss as to know how long to let it go before taking some kind of action, any thoughts?

[gareth h]

Not sure, I’d have to check the lease, but in these times I was more interested in what people thought was reasonable behaviour