The man was found guilty of a racially aggravated public order offence. I’m a legal eagle so will break it down a bit.
There is no such thing as a standalone religious ‘hate crime’. This is an uplift which is applied to a base offence - in this case the offence was a public order offence, and the racially aggravated uplift was then applied as he was burning the Koran.
His ‘public order offence’ was Section 5 of the Public Order Act, which criminalises acting in a "disorderly" manner, or displaying material that is likely to cause "harassment, alarm or distress" to others.
However this Act is usually applied to (for example) people who are acting in a way that is not rooted in freedom of speech, otherwise the ‘The end is nigh!!!’ street preachers would all be arrested. A typical example would be somebody ranting, screaming and swearing in a threatening manner toward shop staff or police, in a way that makes the public feel worried or intimidated.
Luckily his appeal was granted on the basis that his freedom of speech entitled him to do what he did, but what initially happened was they tried to warp an offence into ‘fitting’ the circumstances because of course burning a Koran is, and should be, legal but they needed (in my opinion) to appease communities by making something fit.
I’m not convinced they won’t try to warp other offences in future so although burning a Koran isn’t technically illegal, doing it will bring public order offences etc down on your head.