Heath was a centrist Tory and Blair was a centrist Labourite. But to deny either of them as being not Tory or not Labour is silly.
Johnson has not taken the Conservatives to the centre ground, he has taken them considerably to the right.
Your evidence seems to be Johnson’s adoption of green policies. The error you are making is that green policies are no longer the sole domain of the left, they are very much mainstream now, and impossible for even a Tory Government to ignore.
The makeup and complexion of the cabinet and the Johnson supporters is very rightward.
Trouble for Labour is that the party is very reluctant to follow Blair to the centre ground because of Blair’s legacy.