It's that time of year again when the dreaded tax return has to be done. Or at least think about doing it. I was getting all my required documentation together when I discovered that a company I worked for very briefly (it was a driving agency who I did a few shifts for in the space of about 1 month) have not given me either a P45 or P60.. A check on-line reveals that the company does not seem to exist any more. Any accountant types on here know how to get round this one? Obviously I don't have the full information required for a tax return. From pay slips I can work out how much I was paid and how much tax was taken but not stuff like the company's tax reference number (or whatever the technical name is)..
Shouldn't be a problem.
If you didn't get a P45, you would not have been able to hand this to your new employer, so an entry as previous pay would not appear on the P60 given to you by your employer at the year end. You could double check, by looking at any P45s you did get and making sure the pay and tax on them appears as previous pay and tax on your year end P60.
Similarly, if this was a concurrent employment, your pay from this source would not appear on your year end employer P60.
There is a facility for entering multiple employments on the return. Use the pay and tax details from your last pay slip from the "missing" employer for one of the employment pages. Make sure that the last payslip reflects your accumulated pay for your time there. If it doesn't, you will need to get the calculator out

.
As to the reference number, you might find this on the payslips. If not, see if the return will submit without it. If it doesn't, put the entry as something like 999/99999.
There is what is called a white space on the return, which is for supplementary information. Make a note in that about what you have done and why.