hi,am also putting in gshp in my new-build and am approved for grant.
will probably buy abroad as it is alot cheaper and will still get grant,(checked with sei).
irish suppliers are just charging above the odds for something that with a few internet clicks can be bought and shipped home and still save a few thousand euros .
i'm looking at the moment at a thermia heatpump ,10kw. from poland for under 6000 euro including shipping,
i installed the underfloor heating myself-all it is ,after all ,is laying piping in loops-no degree necessary.
the collector pipe in the garden is basically a jcb digging a narrow trench ,you lay the pipe, backfill, clap hands for job well done.
you still will need a plumber to connect the pipes to heatpump etc,
shopping around and doing your homework can save you alot of money,
oh-and a healty dose of common sense.