Finally got all the bits needed to rebuild the diff. I was waiting on a new crush tube and nylock nut from the local mazda dealer, parts kid there is useless but fortunately my good friend works there and sorted out the correct parts for me. I did attempt to reuse the old crush tube by compressing it in a vice and I did lengthen it by 0.5mm which would probably been ok but as it was only £10 and available I got a replacement.
So last night I set about reinstalling the pinion shaft with the new seal. You have to torque up the nylock nut until it starts to actually crush down on the crush tube, unsurprisingly. I made a diff nose holder out of some left over 50mmx3mm angle and some bolts and set to work.
continued......