If he really was found guilty of 'indecent exposure', rather than say 'outraging public decency', he's got a very good chance of having that verdict overturned upon appeal. For a conviction for 'indecent exposure', the prosecution has to prove that
(a) the defendant intentionally exposed his genitals [which, I'd suggest, is not proven] ; and
(b) he intended that someone would see them [again, not proven, I think] ; and
(c) he did so with the intention of causing alarm or distress [which, I suggest, wasn't the intention here].
(Section 66 Sexual Offences Act 2003)
So the prosecution case seems to fall down on all three counts.
. . . but, yes, it amused me too ;-)