After writing all this, and cycling too hard, it seems to me that I have been failing really badly in treating my haematoma and by exercising so much have caused ongoing bleeding. I am now not using my leg at all.
Addendum: my thigh is heeling really slowly so all the below should be treated with caution.
I have 'karate thigh' right now. I should have blocked or used neko-ashi stance or something, but now I am faced with treatments which are as the OP says vague but I agree with what the OP says: cooling straight afterwards to reduce initial haemorrhaging, warming after once haemorrhaging has stopped.
I am not a doctor and the following items are not medical advice. Hematoma's can lead to calcification, and deep vein thrombosis resulting in disability and death respectively. Several of the items below may increase the chance of these dire outcomes.
1) A full on Japanese karateka recommends strapping lower leg to thigh that night. If you can do this then you will likely be able to extend your leg the next morning but if you sleep with straight leg, and in general, the problem is the inability to bend at the knee. However, strapping the lower leg to the thigh while there is still damage to the veins sounds like it could be dangerous, leading to DVT and death.
2) There are Chinese herbal potions such as Zheng Gu Shui which I have not tried but are available cheaply though the internet. I don't know what they do but I have ordered some. It arrived. It smells a bit like Vicks Vaporub (eucalyptus) and has a similar anaesthetic efficacy to Japanese poultices. It works better on the superficial bruises to my ribs.
3) Stretching and or exercise such as swimming, jogging and cycling are generally recommended so long as you are not going to increase /re-start haemorrhaging. That said, at least one poster has suggested that exercise can increase one of the worse outcomes - the blood turning to bone. Still, I am cycling.
4) Blood letting while still liquid, or injecting blood thinners (e.g. heparin) and then blood letting, or surgery is used. The haematoma YouTube videos are gross! I am going to try natural for a while longer but there are people saying that getting the blood drained before it clots works for a lot quicker recovery. I may go to a hospital to discuss this if my leg does not get better in a week or two and immediately post trauma should it happen again. I did go to a hospital but was told that no local hospital would perform this operation unless the hematoma had solidified and required surgery.
5) I have found that using my heated shiatsu massager (like a spring tipped soldering iron with the diameter of a banana) can work the gunky blood around in my leg to get it fluid enough to allow (3). These are cheap on auction in Japan https://goo.gl/td34HL
This continues to work well. Massage at room temperature takes longer. When I am not near my heated massager I put hot water in a PET bottle and massage myself with that.
6) Pain killing poultices such as generally sold for muscle pain in Japan (Banterin etc) are minimally effective in what they say they do but may help (3).
7) When I was dehydrated with a hangover my leg froze solid, so not boozing and fluids are a (no brain?) good idea.
8) For bruises some are recommending natural blood thinners, such as onion and garlic. I like onions so I am doing that. Aspirin might also be an idea as it thins blood as it reduces pain.
9) There are haematoma taping videos on YouTube. I have not tried (other than the compression with icing immediately after the strike). I have now tried taping, immitating the kinesio taping videos on youtube, using a tape in a hand with long fingers shape. This may help to reduce the effect of gravity (see 11 below) as does a simple bandage compression.
10) Bromelain as found in pineapple and some meat tenderisers can be applied topically. I have not tried this either.
11) Elevation seems to help since otherwise gravity puts the jello blood sludge in one place where it fills the gap between the muscles and thus restricts movement. This may natures way of getting the injured to lie down. I find that lying with my thigh vertical helps improve mobility. I could ride my bike againt after 15 minutes of digital cold vertical thigh massage, as opposed to about half that with my hot massager seated. Conversely after a few minutes of standing, at a convenience store mid ride for instance, it becomes difficult to ride again.
I repeat, I am not a doctor, the above is not medical advice and may kill you.
Here below is the video version of the above, which it may not be appropriate to post (if so please remove, or tell me and I will)