Puffin, Josephine is right, the pt can help with balance issues. The reason your quad gives way is that it is weak and needs a little more work to regain some muscle tone. If you sit with your leg slightly bent in front of you on the bed, you can contract your quad muscle --you will see it move--and then hold the contraction for 10 seconds. You can do 10 or 12 of these several times a day. boring? yes---but it does help the quad regain its muscle tone.
It seems a little early for them to talk of permanent disability---yet you had a traumatic injury and that year of waiting did not help much, I am sure. But, it is time to put on your thinking cap and make your life more fun. We keep a tall stool in the kitchen (which we purchased at IKEA!!) Bob leans his butt on that and it takes some of the pressure off his legs while he is in the kitchen. So, instead of standing for an hour while baking--move around. Sit for a while, stand, hover your butt over the stool!! Find ways to do things that you love---a stool helps, perhaps a single step stool to put your knee on to relieve some of the pressure while standing?
I love your bike!! It looks like fun too. And, it is wonderful to be out and about again, I am sure. Here in the states, we have long, lightweight bicycle poles that attach to the back of the bike and they have an orange flag on top. They work well to warn lorries that you are on the road too!!
I think that some simple balance exercises---will help you a lot. Yes to pt and be specific with the pt---wrtite down the things you cannot do right now and then ask him/her to help you find a way to do them. Walking on uneven ground is always tricky when your legs are stiff. My husband uses Nordic walking poles most of the time--they take as much as 40% of the pressure off your knees, so they are a good thing. Plus they will fold up and fit in your bike basket. bob uses a yoga mat bag to hold his. You have come so far---life is just ahead, don't give up now!!
Your bathing suit story was horrible!!! I warned Jo about capsaipian cream---I used it on my knee and did not wash my hands afterwards. I went to the bathroom and discovered that hot peppers on my hoo ha were not my idea of fun!! I had to scramble fast into the shower!!!!