Please don’t wait for a letter - read the guidance on shielding (link copied below). The guidance describes the group that should be self isolating/shielding for 12 weeks as follows:

“People falling into this extremely vulnerable group include:

Solid organ transplant recipients.

People with specific cancers:

people with cancer who are undergoing active chemotherapy or radical radiotherapy for lung cancer

people with cancers of the blood or bone marrow such as leukaemia, lymphoma or myeloma who are at any stage of treatment.”

IF you are covered by this guidance you shouldn’t be leaving home at all. If you think this group includes you, then call your Trust for their guidance - that way you won’t be in trouble for taking leave of absence. 

Good luck

Dave

www.gov.uk/.../guidance-on-shielding-and-protecting-extremely-vulnerable-persons-from-covid-19