"Black Tea" - that's foreign, not English. In England it's just 'Tea'.
"Black" means "without milk".
Also, every Englishman has their own tea ritual, and it doesn't automatically include silver teapots or sugar lumps. That's only for posh people and social climbers.
For me, a mug of just under a half pint capacity, an Earl Grey teabag shared between the two of us, and served white. ie with milk.
Sometimes Typhoo (because you only get an 'oooh' with Typhoo'), in which case you can dunk ginger biscuits in them.
If any so-called Englishman raises an eyebrow at you, they are attempting to gain points to enable them to climb socially. To counteract this you do indeed allow your little finger to poke out (this implies that you were raised drinking out of bone-china tea-cups, not the mugs which you have more recently adopted) and peer disdainfully at them, whilst offering them a ginger nut. The truly higher echelons of society would never attempt to put you down and are far more accepting than the social climbers. If you provide the eyebrow-raisers with enough rope to hang themselves with they are likely to make some disparaging remark which you can then ignore, sighing oh-so-gently as you do so, and comment about the strange weather we've been having recently to allow them to disentangle themselves from the embarrassing predicament they have dug themselves into. While you continue your own tea-ritual and eat the rest of the ginger nuts.
Rich Tea biscuits have also become fairly ubiquitous as dunking fodder, following the 'A Drink is Too Wet Without One' TV campaign. They do, however, require a different dunking technique to a proper ginger nut, which is basically too hard to eat without dunking.
One more point, if a social climber serves you tea in a bone china cup and saucer it's likely to test your social standing. If you believe this to be the case, the only appropriate response in my opinion is to take a sip, recoil as though it has been served at too high a temperature, tip some tea into the saucer, swirl it around and then drink from the saucer. Ideally whilst throwing your host an "And I dare you to have the balls to do the same!" look. Their response to this will indicate how English they truly are.