At present there is only the offer of the Astrazeneca/Oxford and the BioNTech/Pfizer vaccine, the moderna vaccine will arrive around April.
The next two in line for approval in the UK is the Novovac (spike protein) and the Johnson & Johnson (Jansen Adenovirus). So in todays vidoe you can learn about this vaccine. It is a single dose at present. This may arrive to late for people in tier 4 but maybe it will be approved before tier 6.
If you are interested to learn about the Johnson and Johnson vaccine you can watch this video from Docs at Medcram