The latest scandal affecting the House of Lords is nothing unusual nor is it in itself a reason to change the constitutional arrangements to reform this appointed un-elected body of cronies of elected politicians. There are plenty of scandals that affect elected chambers; humans are weak frail and full of hubris so it is not surprising when scandals emerge. The reason to abolish the House of Lords is that it is simply undemocratic.
Peers are appointed for life and as we have seen can only really be removed for bad behaviour in the chamber. A second chamber serves a useful function of checking and amending legislation, but there is too much legislation these days and it would be better if there were fewer laws for politicians to enact and amend. However if laws are to be amended and checked it must be better for the process to be done by a small body of elected politicians, rather than a large body of those who are retired politicians and mates of those in power who can drink their fill from the public trough. Being a member of the House of Lords is nice work, if you can get it.