Hi,

I have seen some coils of perforated pipe in "been and queued" but
sister company Screwfix doesn't seem to stock it. Is it known by
another name?

The Pavingexpert web site says you can use it one of two ways:
holes-up to collect water from waterlogged ground to take elsewhere or
holes-down to dispose of water into the ground.

It's the latter I am interested in: could you lay a length of this in
a trench and use it as a soakaway?

TIA