How best to insulate/heat solid brick house (as at 2016)
The awkward truth is that you don't have a lot of great options here. External insulation or cavity fill are by far the preferred options. If those are off the table, you can apply insulation board to the interior if you're prepared to lose some floor space, but it's not a perfect solution: there will be big thermal bridges where interior walls and floors meet exterior walls. 10mm of insulation won't do much. You really need to do at least 50mm of a decent insulator to make it worth it.

This approach will be very expensive or labor-intensive (or both) since you'll need to redo all the trim and cabinets, extend electrical boxes and plumbing lines, possibly replace toilets, and things like that. You'll also need to finish the new interior walls with plasterboard or skim coat plaster, if the insulation board you use is cementitious, like Ytong autoclaved aerated concrete insulation panels. The problem with those is that they aren't very good insulators for their thickness--not as good as the plastic foams. But foam boards will need substantially more finish work.