Here is what the leaked guidance from an NHS Hospital Trust says:
‘Doctors are asked to use the standard MCCD (Medical Certificate of Cause of Death) form to certify death. ‘Pneumonia ‘or ‘community acquired pneumonia’ are acceptable at 1(a) on the MCCD. There is no requirement to write COVID 19 as part of the MCCD. It may be mentioned at 1(b) on the form, should the doctor wish.’
You can read the guidance in full here.