Arrg. Too many options...

I need one underground 15mm copper to 25mm MDPE union and one 22mm copper
(or 3/4" BSP) to 25mm MDPE union.

JG Speedfit say their ones are no good underground.

Another says "do not use where end loading is possible".

Another suggests that you need 25-22 reducers before you can use the bunch
of washers and widgets.

All I need are simple, buriable robust adaptors.

Any recommendations?

Ta

Tim