As of April 2021, it appears Vodafone has settled on using 10MHz L09 EARFCN 3623. Please see Radio Spectrum Graphics page for more details.
900MHz 4G at 5MHz for now
Vodafone's 900MHz 4G is using EARFCN 3574 in this scenario, taking the place of UARFCN 2987 (their second U09 carrier conventionally).
Vodafone 900MHz spectrum before LTE refarm
Vodafone's 900MHz spectrum before refarm: two 3G carriers on EARFCNs 2938 and 2987 occupy the first two 'blocks', with the third being occupied entirely by 2G.
Vodafone 900MHz spectrum after LTE refarm
Vodafone's 900MHz spectrum after refarm: some of the spectrum previously used for 2G in the third 'block' is now 4G of EARFCN 3698.
A couple of masts
A couple of masts with the Vodafone 900MHz 4G in/near Leytonstone. There are a lot of possible build layouts that could have been used. These are just a suggestion. The LTE 900MHz means that Vodafone have their own hosted low band on the site.
EARFCN 3698 5MHz