Elesa has come up with a simple solution to fix a handle to a curved surface: the EBP-FLX series.

Essentially they have taken their EBP bridge handle and moulded it in polypropylene-based technopolymer with added elastomer, which provides the flexibility to fit curves of radius from 150mm to 400mm.
The FLX version EBP handles have front fixing arrangement for 8mm cylindrical head hex drive machine screws and are finished off with push fit caps, which are available in matching black (standard) or five other standard RAL colours.
Handle sizes are 144mm and 178mm, with 117mm and 150mm mounting centres. For curves of radius larger than 400mm the standard EBP handles may be used.