score:4
Further down the page you link to it states:
How to travel to the place where youβre quarantining
When you arrive in England, go straight to the place youβre staying to quarantine. Only use public transport if you have no other option, and make sure you follow safer travel guidance for passengers https://www.gov.uk/guidance/coronavirus-covid-19-safer-travel-guidance-for-passengers
So yes, you can take the Tube or a taxi to your hotel.
You will either have to take sufficient food and other necessities with you, or you can have them delivered (as stated further down again on the page you link to). You must not use shared areas such as bars, restaurants, health clubs and sports facilities.