When to negotiate?

[Ohshittt]

Or more the case can I negotiate?

Looking to change jobs and applied for a job advertised as 21 hours a week, got an email stating that job wasn't available and they were taking someone on for 42 hours a week. Asked if I wanted my application put forward for that and I said yes. The more I have thought about it 42 hours a week will be pretty hard with the kids but I could definitely do up to 30 hours. No option to work from home. I have got through to the interview stage. Do I email now and explain my position or wait until i potentially get an offer? Has anyone any experience in this? Thanks.

It could go one of 2 ways. They will love you so much and be able to accommodate the 30 hours. However that does still leave them 12 hours short of what they wanted. Depends on the company / role.
However, they are most likely to be cheesed off with you wasting their time applying for role, going through interviews, to then say ‘actually I can’t do it’.
But that’s not your problem! Why not give it a go!

Thanks for your reply 😊, yeah I don't want to be pissing them off as it's definitely something I would love to apply for in the future when the kids are a bit older if they only offer full time contracts. They can't really be pissed off about me applying as it did state 24 hours then they just changed it last minute, they have since advertised a 24 hour position for the same company but in a totally different role. Seems there was just a mix up in what role went woth what hours. Has anyone else got a similar experience or can offer up any advice? Thanks.