I found the answer.

Misty tell the rest of us.
MPPI

OK MPPI .....Divide bulbs every three years in Autumn.
Dig up the clumps and remove the side bulbs.
The new offsets may take 2-3 years before they begin flowering.

One website said that the Aboriginals in Nth Qld use this plant to treat jelly fish stings.
Did you know that all parts of the bulb are poisonous if ingested, and the sap may
cause skin eruptions, not that anyone wants to dine off it but it is good to know
about the skin irritation. Interesting.....MM

Here is a link that might be useful: Crinum bulbs

They dont warn you how deep you're going to have to dig! Be ready for a bit of intense exercise.
I was relieved to read that they flower better undisturbed because I'm too lazy to get under my clump again.

Hello there from a crinum grower in US (miami, florida)

I grow quite a few crinum in south florida - and find digging up larger bulbs often meant going down as far as 24-30 inches on some of the species here under tropical conditions. I could guess under drier conditions that bulbs could be much deeper and was wondering if any of you found that to be true?

Some types (usually larger bulbs) have sometimes bloomed for me fairly soon after replanting ... I thought it might be attributed due to the stress and size of bulb... but others, especially the smaller ones may often not grow much for a couple of months - and then may not bloom for a year or two.

I find some crinum (like J.C.Harvey) were quite shy after relocating. Some species and hybrids off-set so rapidly I was actually digging up portions to give away after several years. I have also used ropes and pieces of boards to lift and relocate some larger clumps intact when I did not want to divide.

I recommend starting about a foot away from plants and digging down ... so that you stay well away from bulbs.
If you do cut any expensive types by accident try dusting with something like root-tone (fungicide & rooting hormone) and then maybe roll up or wrap the sections back together with some layers of paper towels - you usually end up with additional small plants.... I resorted to that after I had accidently chopped some up when digging too close to them!

Thanks Paul I was looking at them yesterday as I promised one of our Qld GW members a bulb or two, and I do know what you mean, my plants has about eight bulbs close together now so it looks like I will be digging the lot up and pulling apart, actually I may get hubby to do it trouble is he is a bit you know, not so carefull as I.

They are in raised garden beds and the top 30cms is lovely soil but below that is a different thing any way we will see how we go. Cheers .....MM.