If you’re really short of signal then you could consider a 3 element DAB aerial. Bear in mind that DAB is supposed to be a “single frequency network” (for the main stations anyway) so an omni dipole which can pick up a signal from the strongest available transmitter is preferable [but only if there is sufficient signal strength for their use], a directional aerial will obviously make that more problematic. The 3 element model is directional but does have about 3 dBd of gain.
If you’re unsure whether to go for a DAB dipole or a DAB 3 element, bear in mind that you can convert a 3 element to a dipole [which is omni directional] by simply removing the director and the reflector ! Thus the DAB 3 (an aerial which can be converted from a higher gain directional to a lower gain omni) is a good choice if you are unsure of the signal strength in your area.