Hussar 54,
In brief.
4.8km .... not a very pleasant distance in terms of chance of getting good ADSL coverage. Might be longer depending on how your copper is routed. You definitely should not expect 2Mb at that distance.
With my help, I got someone at 5.6km up to 512Kbps .... but it wasn't easy and a fair amount of pure good luck helped.
For starters, try to get yourself referred to the "Long Line Team" at BT. Their engineers are a bit more competent than the normal cable monkeys.
Secondly, try to get them to manually cap your line speed (i.e. disabling the auto rate-adaptive gubbins).
(But given that you've signed up with the worst possible ADSL ISP (BT Broadband), the chances of you being able to do 1) or 2) on your own is probably non existent, and hence you will probably need to escalate your fault in order to see some action....see below.....)
Finally, in terms of getting your fault escalated. Given that you've signed a contract with BT Retail for provision of DSL, your best bet is the CEO's office.
As there is no alternative line supplier to BT ( small village, no cable service ) is she stuck with BT or can she order a new line from a different supplier ?
Satellite. Look at Tooway or similar.
I suggest collectively lobbying BT to get them to install a 'fibre to the CAB' connection from the main exchange down to your village ASAP
Not much point "lobbying" BT unless you can show them a true commercial business case for spending a lot of money getting fibre to you (i.e. you would need to show firm commitments in writing from residents that they would sign up ... and you will need to have a sufficient number of residents to make it commercially viable.... otherwise you'll just have to wait your turn).