The last time I worked for them PAYE it was payment at the end of the month you worked. They would get in touch around the 25th of the month and check to see if you would be there till the end of the month and pay you up to the end of the month.
As a Ltd company and I assume self employed worker you invoice and get paid 30 days later.
This information is possibly a little out of date as it was last year when I was working for them.
Also if you had there old contact details you will need to check there website as they have now moved offices.