There are many left-wing people who were for leaving the EU, so I wouldn’t use that as a measuring stick of left/right.
His voting record is something he has covered; a lot of these votes which make him seem particularly bad (I’m not a big fan of his, despite having read The Place In Between - before I knew who he was - and Politics on the Edge) but from times when people were whipped or ‘encouraged’ to vote a particular way. We found out what happened when he did go against the whip, with even Nicholas Soames feeling that wrath.
Edit: my first sentence in my previous post can be misinterpreted. My meaning is that he isn’t very (strongly) right wing, not that he isn’t right wing at all, as he clearly is centre-right at his most ‘left’.