Haven't seen this latest update posted, but National Rail Enquiries
now says:
Q: If I decide not to travel due to concerns about coronavirus, will I get a refund?
A: At the current time, there is no advice against travelling. However, train companies understand that people will be changing their plans and will be increasing support for our customers who decide against travelling as originally intended.
Train operators are working on plans which will be in place very shortly so that it’s free to get money back on most refundable fares. In the case of the cheapest advance fares, which are not normally transferable, almost all operators will be allowing changes to a trip if someone decides not to travel when they had originally booked for.
We will confirm when these additional measures are in place. At that point, people should contact the retailer through which they originally booked.