Bilt Hamber, Bilt Hamber, Bilt Hamber...… I've tried pretty much everything else and for me nothing touches this stuff. Also I wouldn't cheap out too much on a foam cannon or you'll end up with 4 spare bottles like I have because the actual cannons are useless!!
If you are looking to have a spray bottle with something to boost cleaning power as well check out Koch Chemie Green star, that stuff is amazing and about 5-6 quid a bottle!!!