My main question being is able to tell a subscriber when their next (and subsequent payments) will be taken.

My main question being is able to tell a subscriber when their next (and subsequent payments) will be taken. If a new subscriber submits a form on the 1st of the month for example - and i have chosen 'monthly' as the payment frequency, will all subsequent payments be on the 1st or is it a set 30-day period?

That's right, if you set the payment to monthly then the subsequent payments are set to a 30-day period. As far as I know, we have no way of showing the next scheduled payment. However, recurring payments are automatic and they will receive an email if the payment is successful.