Tax Return/Change of Accounting Date

I’m treasurer of a small church, which is also a trust and a registered charity.

Its income is under £15000. All of this, together with all expenditure, is for a charitable purpose. Also, it undertakes no trading activities and has no employees.

Recently, HMRC asked the church to submit a Tax Return 2016-17.

As far as I can see, Form SA907 2017 seems most appropriate. Can you confirm this?

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/605829/sa907-2017.pdf

With regard to the ‘Return period’ section, there’s a slight complication. Recently, the church, for administrative reasons, changed its accounting year end from 31st May to 31st March. Consequently, there are two sets of accounts that cover the period 6th April 2106 to 5th April 2017. These are accounts for the year ended 31st May 2016 and accounts for the period 1st June 2016 to 31st March 2017.

By law, what is required in terms of submission of accounts with the Tax Return?

Would I get away with submitting the later set of accounts: the period for 1st June to 31st March 2017 (which is for a period of 10 months)?

If this would be acceptable to HMRC, regarding later sections asking for a breakdown of income and expenditure, I assume that I would give the figures that appear in these accounts. Is this assumption correct?

If this would not be acceptable to HMRC, could they deem the Return as being in error or incomplete and charge the church a penalty?

Or am I required to submit both sets of accounts (for the year ended 31st May 2016 and the period ended 31st March 2017)?

If I am, with regard to the sections asking for a breakdown of income and expenditure, would I be required to enter figures based on pro rata, i.e., relevant figures from the 31st March 2017 accounts plus 2/12 (months) of relevant figures from the 31st May 2016 accounts?

E.g.:

Accounts for the year ended 31st May 2016: Pulpit Supply £1800
Accounts for the period ended 31st March 2017: Pulpit Supply £1000

The figure entered in the appropriate section would be £1000 plus (2/12 x 1800) £300 (= £1300).

Do you know of the relevant legislation that covers this situation?