We built our hosting around exactly these requirements.
Encrypts enquiry forms and removes the browser warning that would make a financial practice look careless.
Run info@, accounts@ and individual staff addresses on your own domain, with full webmail and mobile support.
Your site is backed up daily and restorable yourself — sensible practice for a business built on record-keeping.
A local team you can phone, which matters when your site goes down during filing season.