Are Lords and Members of Parliament obliged to register an interest prior to voting on proposed UK legislation?
Yes. They have a Register of Lords' Interests similar to the Commons "Register of Members' Interests".
It is published on line and you can go to the link I've provided to have a look at it.
There is a register of members' interests, and MPs are supposed to say in debates if they have relevant financial interests - but the requirements are weak, and the punishment for breaking them is a slap on the wrist.
For example, if a foreign billionaire hires an MP's partner for a six-figure salary, that's not a reportable financial interest. And if it's discovered an MP "forgot" to declare a reportable interest? They might be asked to... apologise.