I got it working… first I needed to find the .ppd file:
brother_mfct800w_printer_en.ppd
That was needed by cups.
Then my shot in the dark was to take cupswrappermfct800w from the cups wrapper package, rename it as brother_lpdwrapper_mfct800w and put it in /usr/lib/cups/filter.
Finally after playing around with different connection methods ipp://192.168.1.135/ipp/print worked.
I am one happy bunny.