So... you're agreeing or disagreeing that a lawyer can ethically represent a client who he believes "did it" by arguing that the evidence is insufficient?

If you agree, that's walking back on your original comment; if you disagree, that seems to go sharply against 1/2/3.

Edit: As the others note, this is going sharply against well-known legal principles. Do you have any authoritative citation that UK lawyers can't represent clients at all on a not-guilty plea while believing them to have "done it"?