Sorry to read that another cyclist has been injured by a taxi driving moton. I think your primary concern is to maximise your chances of 100% recovery at this stage. Your bike can wait a few weeks, you ain't going to be riding it that's for sure. A broken collar bone and tendon injuries can be nasty, so give them every chance to heal.
This recent post (
https://www.cyclechat.net/ ) a couple of days before yours contains much of what you need to do (my post #8 and a few others pretty much covers all you need to do).
I would make your GP aware asap if they are not already of what has happened to you and your injuries. They should make sure you are getting the treatment you need. They can be very influential.
Get some one to take lots of pics of your injuries. Don't be afraid to be a wuss by asking for help which I guess you will with a broken collar bone.
Were there any witnesses? CCTV?
A personal injury claim by it's nature does take a long time to settle as injuries may take a long time to heal or prognosis may be uncertain. You may also be left with residual pain or restricted mobility which takes time to show that no further improvement is likely. However interim payments from insurers who are liable can be made in the mean time.
If the police decide to charge the taxi driver your civil claim may be delayed until this is resolved. But if the
git, sorry driver, is found guilty of whatever offence, this can make your civil claim so much easier as the standard of proof is higher for criminal proceedings than for civil and can be used as prima facae evidence of liability.
Yes keep a diary and minute all conversations with anyone involved in your case, including whichever solicitor you eventually sign up with.
Anyway take it easy and don't struggle to do stuff. Just get better.