An extract from the government website on outdoor events from 17 May (at the earliest)
Spectators will be allowed at elite sporting events and performance events. Attendance at these events will be restricted to 50% of capacity up to 1,000 people for indoor events, and 50% of capacity up to 4,000 people for outdoor events. For outdoor events taking place in venues with seated capacity of over 16,000, event organisers may apply a 25% capacity cap, up to a maximum of 10,000 seated people. Large business events will also be able to go ahead, subject to the same capacity requirements.
So I guess up to 50% outside capacity at Chelmsford (and maybe similar indoors?)- subject to social distancing I assume? Maybe we'll learn more this evening at the member's forum?