Hi, welcome to GoY, first take off all the fronds, if you haven't already done so, then using either a spade or a mattock, dig the soil from around the stump, if you can't get to the bottom of it, chop it off as low as you can get, and replace the soil, it shouldn't grow back again, but if it does, just cut off the new growth, Derek.

Similar to Derek; Get a heavy duty garden fork and dig it out. If you break off roots and leave them in the ground it doesn't matter as it will not re-grow.

thank you very much I shall be out there now.