GoCardless payment gateway module for nBill (a Joomla extension) - PHP

GoCardless are a direct debit provider in the UK. Up until recently we have been using a supplied plugin absolutely fine, however GoCardless have just launched a new version of their API and the plugin for our accounting system (nBill) no longer works. The software vendor seems to have given up with this extension and has not released any update. We would require same functionality that it has now, or better. We use it to charge invoices ad hoc as opposed to recurring payments.

The task would need a little research, I imagine by downloading and setting up a sample nBill installation and looking through their existing plugin (all on nBill.co.uk).

We are based in Swindon, SN3, and ideally we'd have the job completed by the 12th December.