There are indeed bureaus that will manage your payroll – as indeed can your local TaxAssist Accountant, and it may be worth getting quotes for carrying out this work before you proceed. You may be pleasantly surprised how cost effective they are!
Whichever route you choose, you will need to supply the full name, address, gender, tax code, date of birth, national insurance number, national insurance letter, gross pay to date, tax paid to date and the totals from columns 1a to 1e on the form P11 that you must be using currently for each of your employees.
The bureau or accountant you choose should send you a pro forma to use, ideally two or three weeks before you need to commence - and can supply it in good time for the payroll to be processed without disrupting expected pay dates.
For the 2009-10 tax year, it is a mandatory requirement for employers with less than 50 employees to file their end of year forms online, so it is important that you either use a bureau to process your payroll, or register with the HMRC to prepare for the filing of these forms next April.