the current Labour government have over turned a number of Lords decisions on the basis that they didn't have a mandate as they weren't elected (or some similar argument). What is the point of an upper chamber that doesn't have sufficient clout?

I agree 100%. It's disgraceful that Labour have continually overturned the Lords' decisions, or if they don't get the right result, they just try again instead of accepting defeat. This all costs us a bloody fortune.