OK wrote:
We've got some floorstanding cast iron radiators. I removed them to fit
a floating laminate floor on top of the floorboards. With the radiators
sitting on the new parquet, the radiator connections are now about 10mm
higher than before. What's the best way of reconnecting to the original
pipework? The pipes are steel, so there is no easy way to bend them,
and are perpendicular to the wall with a thermostatic valve giving a
90° turn to connect to the side of the radiator.

Cut holes in the laminated floor. I'm not with you on the parquet,
though. Have you got a parquet floor, ot laminated, or both?