UK starter packs etc

Hi everyone, just wondering if anyone had any advice on the UK starter packs you see on various sites. They usually include setting up a bank account, getting you the equivalent of a tax file number, sim card etc. Are they worth it? And which did you use?

Also, some sites offer visa help where you pay them to go over your UK visa appilcation first so you've no worries about being declined. Is this service worth the money?

Any advice would be lovely!