I really want this job but is this a red flag?

I've interviewed a lotttt of people and I would be very flexible for the right candidate, less so only for one I had lower expectations of. This situation makes me think of when they've been forced to advertise externally but have a great internal candidate who they know is going to get the job.
Having ignored red flags from hiring managers in the past and living to sorely regret it, I would pass. Politely tell them it's a medical appointment you can't cancel, so there's no bad blood, and they might well come back to you with another date.

What an awful situation to be in. Firstly, I'd contact the dentist, explain the situation and see if they will reschedule. If they won't then you are going to have decide just how important the possible job is to you, is it worth risking being taken off the dentist's books? Only you know the answer to that. It wouldn't necessarily bother me that they weren't flexible with the interviews, it may be that it's the only day the interview panel or whoever are available and they probably prioritise that over the candidates availability. I would be a bit put out that they weren't flexible but it wouldn't put me off going for the job if it was exactly what I wanted.

If I really wanted the job I would probably try calling the dentist asap and explaining the whole situation, they might be able to be human about it.

Interviews aren't just about them seeing if you're suitable for the job, they're also an opportunity to see if they fit you and your needs - the fact they won't budge seems like a red flag to me.....something else will definitely come along

No, slipping your mind isn't a good enough excuse. As a prospective employer, that being one of my first interactions with a candidate would be a massive red flag.

I'd have expected a candidate to notify the company on a screening call of any potential upcoming appointments/unavailable days.

That said, it is super inflexible on their end, which might be a red flag for you. But if the company has booked in a day for doing interviews, it may not work for them to have the interviewers available on a different date.

I would expect them to be interviewing multiple candidates that day, and it should be possible for OP to be moved to a later slot.

That they aren't willing to do this does indicate they either have a preferred candidate and they would just be going through the motions with you, or that they are not the best company to work for.

It's a pity, but I would not potentially lose my NHS dentist for a job I may not get.

I do a lot of interviews and we just can't change slots. It is difficult to book the rooms and time in several senior people's calendars in the first place without flexing it for candidates.

I do realise we lose good candidates doing this but there are usually plenty and I don't have all day to spend on trying to rebook.

The thing is, it makes you look inflexible or awkward to them too... even though they and you are not being unreasonable. My work wouldn't change the interview date for a candidate who couldn't make it.

Maybe your message was rude
Maybe if you had explained the context in the way you did here, they'd have understood
Maybe they need to fill the spot ASAP and the next interview date available is too late
Maybe they already have ten fantastic candidates for one spot and you helped them narrow it down
Maybe the hiring manager is going on holiday and back to back and when they're back the other person goes off for two weeks and they cannot wait a month

Many maybes

This is a huge red flag.
You’re not the hiring managers favourite candidate if they can’t make an adjustment. Everyone knows NHS dentist appointments are like collecting rocking horse shit.

They're going to be totally inflexible if you work there around appointments because, of course, you live to work, not the other way around. 🫠

They’ve saved you a lot of hassle in interviewing for a job you likely weren’t going to get!

Whatever their reasons, it’s pretty inhuman and unaccommodating and you shouldn’t have to work somewhere like that

I’d reply truthfully, saying ‘unfortunately this is a vital dentist appointment that I cannot miss, and so with regret I can’t attend the interview and will have to decline at this stage. Many thanks for considering me, and I wish you all the best finding the right candidate’

Sometimes they have commitments they can’t get out of too though. Maybe they only have a short window to interview, maybe one of the panel members is only available that day etc. Whilst it’s not great to offer no flexibility at all, I wouldn’t necessarily write them off as a shit company to work for

Definitely a red flag to give such short notice, no choice of day/time and then refuse to reschedule.

If they can’t accommodate I’d take this as a sign that they have an internal/preferred candidate and you were just making up the numbers. If a company is really interested they would try a bit harder.

I applied for a job in the nhs that was perfect for me. Spoke to the guy I would be working for, he was keen that my skills and experience were perfect too. Then when it came to the interview I got Covid quite badly. They agreed for the interview to be online. My symptoms worsened and I wasn't capable of attending the interview even online. They said tough and wouldn't reschedule. Indicative of their (ironically) bad attitude to unavoidable ill health. Albeit at the time I was really upset, on reflection I dodged a bullet.

Companies often put aside a day or two to bulk interview so it may literally be that day or not at all. Did you ask if you can do different time?

My dd was applying to work in schools and had an interview for one school but it was the same day as her dissertation presentation they wouldn't change the interview so she didn't go.

They don’t sound great but you could phone up the dentists and explain the dilemma to them. They might be gracious… they might not of course

What's the job- is it likely that they will struggle to find lots of good candidates or are they not really going to be that bothered if you drop out?

Did you say why you wanted a different date/time (i.e. did you say it was a long standing medical appointment which most people appreciate would be hard to change, or did you not really give any explanation)?

if they really want you ie experience very relevant for example, they will be flexible

fact they’re not may indicate it would have been a waste of your time anyway

I'm not sure I'd want to work for such an inflexible employer.

Three days' notice for an interview is ridiculous, especially if they're not going to be flexible around people's existing commitments. I would decline the interview, something else will come up.

Likewise, an employer could hope an employee wouldn’t hold this against them!

ultimately the ball is completely and utterly in their court op