I don't think there are many smart pilots around who fly an NDB/DME approach using the NDB and the DME.
Much safer to fly the GPS overlay version - these have been in the IFR GPS databases for donkeys years.
If you set a DCT to "EGKA" or to "SHM" you get a GPS "fake DME" distance, and use the OBS mode of the GPS to track the appropriate radial, outbound and inbound.
I never wrote any of the above of course
A DME is worth having though.
The real problem is that the Shoreham 20 approach is mandatory-DME so you can't even request it at the moment. All you can fly is the 02 NDB only approach and a circle to land - this is fine in daytime and no heavy rain. The MDA is the same IIRC since the 20 IAP is 800ft and while the 02 IAP is about 600ft, the minimum for circling to 20 is again 800ft. The temporary full-GPS IAP which existed during the trial didn't improve on the 800ft which was a real missed opportunity. What is the point of a GPS approach if it offers the same minima as the conventional one?