You should have contacted the police on the day - as everyone's said, 3 weeks down the line you've done yourself no favours. Any tap, expect a "whiplash" claim from the other party. All the more so if you went into the back of them and you suspect they were playing the brakes to arrange a coming together. Whiplash claims are very difficult to fight as it's all pain based and you can't measure pain.
At least now you should have their details via the claim, including vehicle reg. Make a non-999 call to the police or nip down the station. Take your documents with you to save time (license, MOT and insurance certificate). The police may ignore it because it happened 3 weeks ago - but at least you can say you've done the right thing by telling them (even if you are a bit late about it). Push them for an incident number to give to your insurance company - that way they at least note down your point of view.
And when dealing with insurance companies over the phone, don't accept advice from the first person you speak to. That person answers the phone when it rings - the person qualified to give you legal advice almost certainly isn't on general phone answering duties.
At least now you should have their details via the claim, including vehicle reg. Make a non-999 call to the police or nip down the station. Take your documents with you to save time (license, MOT and insurance certificate). The police may ignore it because it happened 3 weeks ago - but at least you can say you've done the right thing by telling them (even if you are a bit late about it). Push them for an incident number to give to your insurance company - that way they at least note down your point of view.
And when dealing with insurance companies over the phone, don't accept advice from the first person you speak to. That person answers the phone when it rings - the person qualified to give you legal advice almost certainly isn't on general phone answering duties.