Help! Medical HST interview prep advice

I've got myself through most of IMT relatively successfully and I'm applying for HST this year.

I feel like I'm maybe in a minority that I've only recently decided what to apply for and I don't have a particular specialty specific portfolio.

I did very well on IMT interviews using only medibuddy (which I didn't find very helpful) dropping 1 mark overall.

I'm applying for Resp and AIM with a view to try and get Resp. I suddenly feel like everyone around me is in on a secret I'm not and I'm panicking about whether I need to be paying for £300 courses or if my tried and tested ISC book + some friendly regs' help with advice and mocks is enough??

Being honest I just want to be not unemployed and to work where I've built my life. I can't believe I'm nearly 30 and have to tell my partner we can't settle down and buy etc because there's a very real prospect of my unemployment imminently.