JB Hi-Fi currently has a buy one get one free promotion on their Dr Who DVD and Boxsets(jbhifi.com.au).
This stacks with the 20% off, which finishes this Sunday (10/01/16). Unconfirmed, but this may also be used in conjunction with the $20 off $100 vouchers, if you have one.
The best value seems to be the Boxsets starting at $12.78(jbhifi.com.au), which give you 2 DVD series in them, netting you another 2 DVDs for free: Works out to be around $3.20 per series.
For example, add this(jbhifi.com.au) to your cart, and this(jbhifi.com.au) to see the resulting price.
The store I visited at Brighton seemed to have a lot of stock, but not all the items listen online. Some weren't even stickered so make sure if you go in-store, you ask the staff about this deal.
Is the "Shift" key broken on your keyboard?