@preet86 Would look on the Sky Q site for a solution, sky mini connects to the sky q box in there own kind of mesh system with the aid of the Sky router that you used previous, has take sky years to get it all working so you may find that the EE router and Extender is not going to be your solution. First have a look to see if the SkyQ and the Mini have there own network, should be easy to spot as it will have a sky SSID name unless you kept that name for the EE router system as a quick setup option.
if you think it was the deco that sorted it out, you could put it back on as quick test to see how/if it works. Powerline has been successful in connecting the mini boxes back to the q box via ethernet, and you should see that in the sky q forum.
