You should continue to input supplier invoices separately, where possible, into your bookkeeping software and reference as before, maintaining them with your VAT records, either digitally or as paper copies.
Where an invoice includes a number of transactions, where the purchases have different times of supply, for example, the monthly Pet Cremation Services invoice or your monthly External laboratory invoice, as long as the transactions are within the same VAT period, you may record all supplies on the invoice as being at the same date i.e. simply enter the total as shown per the invoice.