Please note that printing to ANY Brother printer, from Android, will result in poor quality output (jagged text and geometric shapes). PDFs printed via Android are mostly unreadable, as text often becomes an illegible smudged mess, and graphics become artifact laden. It's a known issue, and Brother don't anticipate releasing remediatory firmware (and software update) within the next 18 months (from Jan 2016) at least.
This is from their T @ C's ... "This Brother UK Ltd (BUK) promotion is valid only on the above Qualifying Products which must be purchased from a Brother Authorised Dealer within the United Kingdom, details of which are available by telephoning 0333 777 4444." I actually rang and ask and they gave me an unambiguous No to amazon as a Brother Authorised Dealer
Interesting - they certainly qualified as a reseller in 2013 when I claimed cashback for my Brother laser printer. I'd agree about Amazon marketplace resellers, but Amazon themselves are normally OK as they supply UK stock.
Anyone reading this, please beware! Amazon are not an authorised Brother supplier and therefore you would not qualify for the cashback.
There was a toner trick mentioned in this brother deal. Might work on this printer too. https://www.hotukdeals.com/deals/brother-mfc-l8650cdw-colour-laser-multifunction-286-37-leo-office-supplies-with-2344532?p=26961373