I'll take a guess.
Not sure what you asked your solicitor to do 13 months ago, but he decided that he could charge you £150 (?) for a company that he paid an agent £25 to set up. It turns out that you didn't need this company after all so he lost track of the relevant documents (most agents send these through as PDF files these days so they were probably attached to an email that was archived off months ago).
One of the documents that company formation agents send is a Stock Transfer Form. This is the document that transfers ownership of the company from them (because they set it up, they own it initially) to you. Once they have signed this STF (and resigned as directors and company secretary), as far as they are concerned they have washed their hands of the company - it is over to you!
Time passes. Everyone has forgotton about all of this. Except Companies House - they recorded the date the company was formed, and 12 months plus 28 days later they expect an annual return. They start writing to the directors and company secretary of the company (I guess that's you) at the company's registered address. If you are lucky, your solicitor gave your address to the company formation agent so you have a chance of knowing what's going on. If you are unlucky, it went to their address and sat in an administrators in-tray for a few weeks while they worked out what to do with it.
So now they have sent it to you, overdue? And you have had to chase them for the papers?
Never mind, even if it is late noone is going to be prosecuted over this. You will have to pay a late filing penalty, £150 or more, and because you do not have time to go through the online filing application process it is going to cost you an extra £15 for paper filing. If your solicitor has caused you this delay, and you fancy a fight, write to them demanding the fine and extra £15 (do NOT delay paying the fine yourself, pay it straight away and get it back from Useless and Crap). If they resist, look out details of their complaints procedure - if they didn't give you this when you originally instructed them, point that out to them too, and ask for a copy. If you don't get satisfaction, take it to the Law Society.
Look for another lawyer, and next time you want to form a company, deal with the agent yourself. Google company formations, there are hundreds (some are better than others of course). You do everything on line, pay with a credit card and a few hours later you have a company.
There are some other things that should have happened since formation - a board meeting dealing with various things for instance. But noone is going to check that this has happened and been properly minuted. I don't think I would be breaking any trade secrets (I am not a lawyer) by revealing that the date that various documents and registers say something happened is not always the date that that thing actually happened.
Don't worry, this sort of thing goes on all the time. Over a third of a million companies are formed in England and Wales every year, and over 150,000 companies are late with their annual returns. You only get prosecuted for persistent or dishonest breaches.
If you want professional advice, go to an accountant. Accountants are (obviously) experts in company accounts, and most have at least a working knowledge of company law (certainly as far as annual accounts and returns are concerned). Solicitors know very little about accounts, and many do not have much practical experience of company law. There is another animal called a Chartered Secretary, who should know just enough about both to be dangerous, but they don't get out much .
But dealing with a dormant company should be really easy (if my wife is reading, yes I know) so save your money and do it yourself. There is an excellent booklet produced by Companies House which tells you everything you need to know to manage a dormat company.
The usual caveat applies to all of this of course - this does not constitute professional advice.