I'm wondering if I'm assuming wrong that accountants can work magic and find deductions etc.
I mean surely they will try to find you the most they can rather than ask what deductions you have if you've already handed over your expenses.
I'm referring to Payg & home office s/e income & shares
Accountants don't work "magic" but they should help find potential deductions or offsets that may apply to you.
I'm an accountant at a mid tier firm and at the very least we always run through two checklists with clients to help us ensure they've disclosed all their income and deductions. Then once we know what the client does for a living we usually talk about some occupation specific deductions (ie: hairdresser would usually have scissors and clippers or a PE teacher at school usually requires sunglasses and sun block).