Lots of excellent advice on this forum, check out the ‘stickys’ at the top.
I suggest you don’t ignore the ticket, if it did go all the way to court (most unlikely) you would be in a weaker position. Do not ring (expensive) or e-mail them (no proof of receipt), put everything in writing.
Write a civil, to the point letter and ask them the questions i.e. How did they get your address and proof of time scale etc. Don’t forget, they are accusing and therefore it’s their responsibility to provide evidence, which they don’t like doing (or can’t).Do not admit or deny who was driving, that way there is no incrimination. When they reply with the standard letter, be civil, thank them for their correspondence but re-ask them for the details of proof which they will have undoubtedly left out, their next letter is usually the same nonsense, then you civilly explain to them that until your receive the information you asked for you will cease correspondence with them.
They then pass it to a collecting agency who will send a threatener, just say you are surprised to receive their letter as the demand is in dispute and refer them back to the ticket issuers.
Now the fun will start with the collecting agency, letters will arrive threatening all sorts. Just remember this, they cannot make any demand for money or goods except with a county court judgement, they cannot enter your home, if they make threats, in law, it is harassment, they are not bailiffs, a bailiff will only call if you fail to pay a ccj. It will never get to court, if it does they have probably refused to supply your very ‘civil’ demand for proof etc.etc. and there will be no case to answer. They like to make money not spend it !!
Keep copies of all the letters you send and keep all of theirs and the envelopes they come in, it’s been known that a collection agency will date a letter 14 days before you receive it so as to claim additional fees.
Be strong, don’t doubt yourself, you have this forum behind you.