Hi Nick - glad to see you're making progress!
Keep an eye on that "feeling" you experienced but try not to over-analyse at this stage. This is very
rich coming from me as when I was a week off crutches and was still having pains and the odd click I was convinced something had gone wrong etc etc... my knee feels "loose" - did he tighten things up enough?... why does it hurt so much, should it still be hurting like this?... why does it feel like it's going to lock?... etc etc.
The fact is, your knee will never be the same. FACT. Your knee will never feel the same again. ALSO FACT. You will, however, not notice the difference any more unless you really focus, after a certain point.
Give yourself a chance.
The healing processes that are going on right now are many, and don't just relate to the new ligament bedding in, or to the tendon repairing itself (after having it's middle third cut away!)
There are proprioception issues (nervous feedback from various mechanisms around the joint that help you with subconcious spacial awareness and balance), plus a lot of atrophy in all muscles around your leg, not just the quads (although you'll be hyper-aware of them after that butcher had his way with your tendon!).
The bottom-line is that you have a brand new leg that you are learning about all over again. How it works, what it will do, what it won't do - and while over the years full use of this leg has been a sub-concious affair, for the next few months it will be a concious one. This means you will feel sensations that previously, were so common-place your CNS didn't bother to make you aware of them. Ie; the torque in the knee when you twist on it - the shift in ground level as you walk etc.
What I'm trying to say (and making a long-winded hash of it!) is that it becomes very easy to over-analyse what you are feeling and worry yourself unnecessarily. Don't over-reach, do only
what the physio says you can do - but do it hard!
Sounds like you're doing well to me mate.
Rock on - rugby awaits!!!