As I've said previously let us not be distracted by calls to opposition candidates to prove their "track records".
Opposition candidates can only have a "track record" when one is able to do something in a ward between electioneering periods.
This means that opposition parties and their candidates are given a level playing field, even between elections. (And it would help if ward boundaries are not drawn and redrawn for some unspeakable reason.)
I ask the following questions as someone who's been away from home for too long, based on what I've observed of UK politics:
Can opposition candidates go on "walkabouts" or would they face harrassment, eg being construed as an illegal assemby?
Can opposition candidates sit in on local Council/town hall meetings and voice concerns about work done (or not done) around the constituency?
Can opposition candidates interest the mainstream media in publicizing their work in supporting the campaigns of the constituents if these campaigns are not supported by the sitting MP?
What opportunities are there for opposition candidates to be effective opposition if regulations are in place to obstruct any work they might try to do?
If it is clear that opposition parties and candidates do not have a level playing field, then it is an "own goal" for the sitting MP, whether PAP or not, that opposition candidates do not have a "track record" to speak of.