Best way to DIY clean DPF?

Hello, 
Just purchased a 2017 Auris in August. For a few weeks now the DPF indicator has been turning on very frequently. I travel to work every day around 30min on the motorway. Even after almost an hour driving on the 4th gear non stop to try to clear the filter it has not helped. 
Was told by arnold clark that just checking whats wrong with the car would cost me around £300, without any service. A friend told me to look into DPF cleaners and I have, Just not sure what the best option for me is or whether these are even worth buying.

Thanks in advance!