I will be updating my Emergency First Aid at Work certificate in a couple of weeks time with the St John's Ambulance. I have to renew my certificate every three years by doing a course in person but in between I sometimes do online courses to keep my awareness of basic first aid topped up. These don't take long to do and could help you to make a real difference to someone in need of help. Here is a link you may like to use to one that is available for free during the pandemic:
The Red Cross also have online information:
Earlier in the pandemic I did another one with SJA which presented me with scenarios and I had to select the appropriate actions (suspected heart attack; heavy bleeding; unconscious person; choking). It was excellent and did identify some areas where I needed to brush up my knowledge.
Even though I have been doing first aid courses for over twenty years now (usually emergency first aid but I have done the three day more thorough course as well) as with everything if you don't use it regularly it is difficult to remember everything. I am very glad that I have not often been in situations that require me to use my first aid skills but this lack of practice makes it even more important that I keep refreshing my knowledge.
Do also keep an eye out for where you can access a defibrillator near your work or home, you can look them up on this site: https://www.heartsafe.org.uk/aed-locations