Self employed, but working in CIS scheme - do I need to 'cut' payslip on tax year change week?

LittleBrownHouse

Quite long shot, bit unusual situation and I am struggling to find the correct solution. Perhaps someone can advise me, who has been in similar situation.
Situation:
My partner is self employed. Not typical though. He does not invoice people for his work. He works in construction industry, gets jobs via agencies.  Said agencies also manage his payments and  pays his income tax (this is  governments CIS scheme).
He  gets paid weekly, so pretty similar like all standard employed.
Only difference is that his NI payments are not deducted and he needs to do self assessment at the end of tax year, pull together all his income, tax paid and expenses + pay NI contributions. All clear there.
Confusion: 
So Tax year stars mid week - on 6th April, therefore on week commencing 4th  April there are 2 working days in previous tax year and 3 working days in new tax year.
He gets his payslips weekly and they are never cut off in the middle for new tax year start.
For example he got paid that week for 40 hours, certain hour rate and from that income the agency fee was deducted,  as well as income tax.
Question:
For his self assessment purposes: does that payslip need to be split exactly as per  tax year (divide hours  and proportionally tax paid  and fee for them 2 days out of 3 and leave them 3 days for next tax year?) Or it can be done as in example: 
**W/c 28th March - 3rd April: old tax year
**W/c 4th April: full payslip added to new tax year
I have asked the question to agency, but they are not helpful and go in rounds, do not answer questions really.
(I have even asked them to send a summary of payments for previous tax year.. which they did. But for some reason in summary they did cut off on 27th March..even following week 28/03-04/04 still belongs to same tax year and he was working with them and got payslip.  So I take their summary is incorrect).

I am helping him with his assessment and we probably will do as in 2nd example and will move 2 days from old tax year to next tax year...hope that wont be an issue with HMRC.

I would appreciate any advice, if you have come across or are in similar situation.

thank you in advance.

comeandgo

I would imagine your partner is on the cash basis system so it is actual payments he has received during the tax year, not the dates they relate too.  Remember to gross them up to include the tax suffered too.

sheramber

it is the date he is paid that is relevant. 

Any payment received after 5 April is the new tax year.

LittleBrownHouse

Great.. I was so concentrated on actual dates worked in tax year that completely overlooked payment dates.
You right..even he worked week in prew tax year, payment was made on new tax year, so it goes across. 

Thank you ever so much.