If you are acting on behalf of your clients (as an accountant, bookkeeping or assistant - whatever the role may be), you’re probably better of going for Affinity, which will work out more cost effective.
There’s an overview on Affinity here: QuickFile Affinity overview
Regardless of how you use the individual accounts (for full record keeping or just submitting VAT returns via the bridging module), it will work out more cost effective.
To close an account, you can use the “Clear data” option: How do I clear my account?