New AST same tenants directly managed, well mostly...

Tenancy Types and Management

Hi, I'm now into my second year as Landlord but only managed the property in the first year. An agent initially set up all of the paperwork. I have now set a new tenancy directly (signed and we both have tangible copies) and I've used the NRLA couples AST version with an addendum. As I've issued the new AST for a further year, advice has been to serve all other documents to avoid any issues later. I'm just pulling all of the documentation together and have a few questions:

1. Can I serve all of the additional documents by email if they have agreed to receive them as such or are there some that must be delivered via post/hand?
2. The agent lodged the deposit with TDS who have said it can stay lodged but that I can apply to have it transferred. Is this necessary?
3. Should I request all of the details held by the agent for myself and my tenants to be sent to me or destroyed where necessary or do they have a duty to hold this information (I know they have to hold financial information but should they hold anything else)?
4. Have you heard of Goodlord Let & Rent Protection Insurance? The agent set this up last year. Is it worth renewal as this would be done via the agent again or if I were to change to another company (if I can find one) would my tenants have to go through all of the checks again?

Thanks for your support.
Rachel