Note that the West Lothian Question has raised its head again and that a committee has been set-up to investigate the issues involved.
Basic problem is Westminster being simultaneously a UK and an English Parliament.
SNP and Plaid Cymru never vote on English matters; so the culprits are primarily in the ranks of the Labour Party.
Seems that the LP is now 100% Unionist with only challenge coming from Northern Ireland: strange reversal of the Party's historic position!