Hi b5mac, glad I was of some help.
The great Horntail
Urocerus gigas is a native and and relatively common in GB. The female has the ovipositor ie horntail whilst the male is a less impressive beast.
The eggs are laid (drilled into) conifers where the larvae burrow through the wood. For this reason horntails often turns up far from their original location as they will emerge from wood used as fencing posts and other industrial uses.