Husband & wife wedding videography business registered as a business partnership with the date of business commencement being the date of the first wedding filmed. However, a substantial amount of deposit income was actually received in the previous tax year and a lot of it as much as a whole year before the start date. My question is - shouldn't the correct start date be when the business was in a position to trade? Ie office/editing studio established, advertising & marketing done, non refundable deposits for future work taken? If this is correct, is it possible to change the start date of the partnership with HMRC after it has been registered and what are the penalties for late registration & submission of tax returns? Thanks in advance!