A question that has recently bugged me as a result of one of those interweb trails that take you from one place to somewhere you did not expect.....why did the HS(BAe)146 not use the Rolls Royce/SNECMA M45H engines used on the VFW614?
Next to the BPR/noise issue mentioned above, have a look at the timeline. The VFW614 first flew in 1971, the BAe146 in 1981. Ten years later they were looking for a different generation of engine. Another one is that the M45H engine was developed for a very specific short stage length. The BAe146 was aimed at a more flexible market.