My favourite nut roast recipe seems not to be online any more!
However, this tip may still help.
I used to find it fiddly having to slice the roast just as everything was going on the table, and it used to crumble. So I now cook it a day in advance, refrigerate and slice it cold, put it back in its (lined) loaf tin, and heat it in the oven for half an hour or so before serving. The slices then are easy to serve, and look good if you've added any contrasting colours, e.g. herby stuffing or whole pistachio nuts.