Once the primaries were installed, the oil tank was fitted. This turned out to be a bit fiddly. the oil tank was dropped into position in front of the engine and the M8 bolt was loosely fitted in the top bracket.
The two P-Clips that secure the bottom flange to the chassis really only had one possible position - however, this was at odds with the diagram in the the manual. At any rate, the P-Clips were fitted but getting them to close sufficiently under the rails so that the nyloc nut could be secured was not easy.
Once the P-Clips were tightened, the resulting gap between the upper chassis rail and the tab on the front of the oil tank was measured. The corresponding number of washers was then introduced under the tab and the M8 bolt was tightened. A satisfying result.