Today, the OGP has published model forms of the Covid-19 Site Closure Supplemental Agreement, which are compatible for use with standards forms of PW-CF6 and PW-CF7 respectively. These should be used in conjunction with the supplementary guidance notes (as appropriate to the date that PW-CF6 or PW-CF7 contract was made) and the Covid Costs Notices published by the OGP on 26 February 2021.
Further information is available here.