Further to my previous post, there are other (more authoritative and independent) version of the notional result for 2005.

The BBC shows the notional percentages for 2005 in 'Lewisham West & Penge' as follows:
Labour 46.3%
Lib Dems 27.1%
Conservatives 21.6%
Others 5%

Clearly the big difference here is the second place position and the size of the Labour majority. This analysis benefit Lib Dems most but still leaves the Conservatives stronger than the actual result in 2005 in Lewisham West.

Ah, the fun of statistics