How long to move from Red Hats in swimming?

[WittiestUsernameEver]

DD had just turned 4 in mid December 2023. Started foundation level lessons the Jan after.
She has a 30 minute group lesson (anything from 3-8 kids a week)

She swims for fun 2 x a week otherwise.

She's extremely confident, happy to be out of depth, jumps in happily ), can do forward rolls under water, retrieve weights to a depth of 1.2m

(but she could do this before starting lessons)

How long would you expect her to be in red hats/how much progress should she make in the 4 months.

Just trying to guage if her teacher is good/of she's on track etc.

Other parents are saying their kids have been in red hats for a year or more!

The colour of the hats match the colour of each stage of the Swim England programme (not necessarily immediately obvious, but if you check out the badges and certificates you'll spot it), moving through a rainbow. Red is stage 1, orange is stage 2 etc. It makes it easy for the teachers to identify which child should be where in a large centre with multiple lessons taking place at once, so no beginner is accidentally chucked in with the level 7s.

OP, it totally depends on the child but given what you've said you do in addition to the lessons, 6 months seems fair on the face of it.
IME, the sticky stages are the odd numbers. Stage 1 is all about water confidence and putting their faces in, as well as 'travelling' 5m. What the latter means will vary by pool and what they need for safety - some where the DCs are always out of their depth will insist on this being swimming unaided either doggy paddle or just kicking on either front or back, others it will be walking across the pool, but for most it will be kicking with a noodle based on the pools my DCs swam with, where friends trained and where I trained.
I would recommend taking a look at this:
www.swimming.org/learntoswim/learn-to-swim-stage-1-award/
See which of the competencies your DC can already do, then spend a bit of your other 2 weekly fun swims helping them to master the others. Many get stuck by not wanting to get their face wet, but it might be something else that's missing such as their push & glide? Once you are confident they can do everything consistently to the standard expected, if they still haven't moved up I would be questioning the teacher or swim school coordinator about it to find out what else they need to do.
I would also recommend the holiday crash courses if your pool does them. They learn much more in 5 consecutive days than once a week for 5 weeks, and the courses usually work through every competency so each one gets the opportunity to be ticked off (IME there is often 1 skill that only gets covered in lessons once in a blue moon).

As a point of comparison, I have friends whose DCs had no previous swimming experience and were very under confident. Their DC was in stage 1 for nearly a year. My DCs did Ducklings first and went into stage 1 already able to swim 10m, so they were in stage 1 for 6 weeks, then stage 2 for another 6 weeks (the time it took to work through and tick off all the competencies), before getting stuck in stage 3 for some time learning to breath to the side. Both also got stuck in stage 5 for a long while, and DD1 in particular was held up in stage 7 for 6 months after she'd passed everything else as it requires 25m of each stroke at Swim England standard (ie race-legal)... She just couldn't maintain getting her arms over the water simultaneously for the full length of fly 😩 It can be very frustrating when they're just held up on one point, but if you know what it is you can help them or offer sympathy whilst you wait for them to grow and develop the required core strength!

It can also depend if there are spaces in the next stage up. I know lots of chn ready to move up but can't because they are full.

My DS was in his red hat group for two years! It was because there was no space in the next classes up for him to be able to move up into. He became quite demotivated and was saying he didn't want to go any more even though he loves swimming, he had just outgrown the class. We switched him to a different swim school and it was the best thing we ever did, he is thriving now.

As others have said, different pools have different standards. What I have found though with mine is that the early stages for 4-5 year olds is often less about their swimming ability and more about their listening skills and coordination. My 5yo is in stage 2 and will probably be there for a while despite the fact she can do all the asa elements because 1) she’s tiny compared to the older kids and therefore less powerful so they don’t want to move her up to get stuck in the higher stages 2) her listening skills can be up and down and 3) sometimes she struggles a bit with coordination with floats and doing some of the exercises.

They also will often add extra requirements that they never tell you. Eg stage 2 in our pool wants kids to have a decent breast stroke kick before going to stage 3. There’s no mention of that in the asa competencies and I suspect most pools have these extra things they’re after.