These are quoted from the official guidance directed at priests. I will refrain from commenting, except to add emphasis, here and there:
In response to government legislation, the archbishops and bishops have advised all churches to close completely during the government lockdown. This is both to reduce travel and to help to model best practice in maintaining social distance.
The Archbishops’ Council is aware that some elements of what the Archbishops are asking goes beyond what is required by government but considers that this shows the Church modelling the very best practice* in promoting social distancing and reinforcing the message to stay home in order to protect the NHS and save lives.
Can I livestream a service from within the church?
Should I stop access to the site, as well as to the church building itself?
Ensure that vehicle access to your church is secured if possible, so that vehicles cannot easily access the building itself. If you have gates, close and lock them.
Can we do anything to keep an eye on the building? ...
There will probably be members of the congregation taking their daily exercise or shopping for essentials whose route will pass by the church. They could check if all looks well from the outside, without entering the building... A pair of binoculars can be helpful in assessing the building.
Can a nursery still operate from church premises?
The government has issued specific advice for early years and childcare. Early years provision can stay open for the children of critical workers and vulnerable children.
Correcting the time of the clock, winding the clock, and raising or lowering of flags does not justify the risk of a lone person climbing the tower.
Can I collect post that is delivered to the church?
Yes, but only if this is done as part of exercise or another essential trip... collecting post cannot be considered an essential activity that would justify a separate journey.
Can I access my closed church to do the cleaning? ... Cleaning cannot be considered an essential activity that would justify a separate journey. Please be aware that a building in which someone who may have the [birdemic] has been is considered ‘dirty’ (i.e. may contain infection) for 72 hours afterwards.
Should we still pay our parish share?
Parishes should aim to pay as much of their parish share – ideally all – as they are able. The work of the Church continues, albeit in a different way.
Are we allowed to lead worship outdoors, if people maintain 2m distance?
No. The Archbishops have given clear guidance that our church buildings are closed and there should be no public worship.
Will food banks have to close?
Foodbanks and services such as GoodSAM should continue where possible under strict guidelines
The church (or a hall) is used for blood donation, can it continue?
Yes. Donating blood is an essential activity, and travelling to give blood is allowed.
My summary - The Archbishops have decided, going beyond government requirements, that (ideally) churches should be closed, locked, nobody should enter the building or their grounds, and no public worship should occur. On the other hand, church buildings may still be used for non-Christian purposes. And the congregation should continue to pay their full tithe.
* This phrase is the nearest to an explicit confession of being engaged in virtue signalling, that I've yet encountered. Some more Church-birdemic themed posts can be found by following links from here.