My post office is open as is Hermes drop-off, so shipping is still an option. Royal Mail delivers, or at least did so this morning and Hermes dropped something off yesterday. i.e. it is possible to function.
I'm spending the time not going to fairs by listing some of the many things on the website that I haven't got around to doing so far, putting some things on eBay and sorting out the numerous storage boxes of coins in the pending pile. I think most dealers have a lot of things not listed on their sites, so stock is not necessarily going to be a problem.
Prices must take a hit somewhere assuming some people will have lost their disposable income, but at the top end, money is not a problem with only a bunker mentality inhibiting spending. The world unlikely to run out of people on ebay buying things for a quid, so this offers probably the strongest market for selling into. Stock markets coming off 20% will have made a few people switch into alternatives. Unusually, gold has not spiked to any degree, so either people are sitting on loads of cash, or they are buying alternative assets. Property isn't an option as viewing/surveying etc is problematic, so it boils down to assets you can buy over the internet. Good for coins, or at least relative to some of the alternatives.