the dslchecker speeds show slightly lower that these figures but still higher than current speed phone CS 151 and complain that you are below estimated speed and need engineer visit. it may be there is a line problem or that your line quality is not as good as expected ie aluminium
bear in mind alll speeds quoted by BT are connection speeds not actual download speed - no ISP guarantees download speed
big connection speed difference mainly due to draytek connecting with 3db noise margin which is boosting conenction speed
Have you confirmed the speed shown by the Draytec with a speed test?