[Lottiman]

Mine go in 6'' deep with a sprinkle of soot leave flat and earth up when they are up 6'' and then again a little more later on. 

[devonbarmygardener]

I'm a trencher of spuds or I grow them in bags - in which case they get earthed up anyway as I plant them in the bottom of the bag

The only spuds I put in the allotment beds are ones less susceptible to slug damage. I do throw a few slug pellets around now and again.

I tried nematodes one year - I swear they escaped from my plot and went to my mate John's plot as he had hardly any slugs that year!!
Either that or they died in transit via the post office and John was just lucky!

[Ivor Backache]

As regards the slug pellets, as MoS says, there are slug resistant varities, but I also plant with a handful of wood ash from my open fire.  I hoard the ash over the winter to use on the plot come spring.  Its an age old trick, but really does seem to work 

I have not heard of this so I googled 'wood ash potato trench' and found it is not a good thing to do. Wood ash makes the soil alkaline and that induces scab on potato.

[New shoot]

As regards the slug pellets, as MoS says, there are slug resistant varities, but I also plant with a handful of wood ash from my open fire.  I hoard the ash over the winter to use on the plot come spring.  Its an age old trick, but really does seem to work 

I have not heard of this so I googled 'wood ash potato trench' and found it is not a good thing to do. Wood ash makes the soil alkaline and that induces scab on potato.

Never had a problem myself.  Maybe a small handfull at planting is not enough to make the soil pH really change?