We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a seven-beam receiver on the Parkes telescope, refered to as MX observations. Paper I provides sensitive unbiased coverage of a large region around the Galactic Centre. Details are given for 183 methanol maser sites in the longitude range 345{deg} through the Galactic Centre to 6{deg}. Within 6{deg} of the Galactic Centre, we found 88 maser sites, of which more than half (48) are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative of many sources at the Galactic Centre distance and beyond, and confined to a thin disc population; there is no high-latitude population that might be ascribed to the Galactic bulge. Paper II spans the longitude range 6{deg} to 20{deg}. We report the detection of 119 maser sources, of which 42 are new discoveries. Paper III covers the longitude range 330{deg}-345{deg}, yielding 198 masers, of which more than 40 per cent are new discoveries. Paper IV span the longitude range 186{deg}-330{deg}. We report 207 maser detections, 89 new to the survey. This completes the southern sky part of the methanol multibeam survey and includes a large proportion of new sources, 43 per cent. We also include results from blind observations of the Orion-Monoceros star-forming region, formally outside the latitude range of the methanol multibeam survey; only the four previously known methanol emitting sites were detected, of which we present new positions and spectra for masers at Orion A (south) and Orion B, obtained with the Multi-Element Radio Linked Interferometer Network (MERLIN) array.