Having read a huge number of similar posts around the net I have today replaced the drive in my 5045GDL+ with a Liteon IHAS 324-32 (£16.99 from Play.com), using a SATA to IDE adaptor (£19.99 from Maplins). I butchered the case of the drive to make it fit when I should have simply cut a damn great slot in the face of the 5045 and fitted the new drive easily (other than only using two screws to retain the drive instead of the four of the original unit, and having to drill through the case of the dvd drive to get at the screw posts), leaving the dvd drive's front bezel alone and making it look less of a mess aesthetically. I'll learn for the next time. More happily, it all works , even fast forwarding; albeit the FF is less smooth than from the HDD. Everything plays, records, transfers in either direction, and still remains multi-region.
If I did it again I figure that it's less than an hour's work.
G, March 2010