Looking for a budget latching relay which needs manually resetting once triggere

tl;dr version:

I'm looking for a mains-voltage simple latching relay which will simply open a circuit as soon as it's triggered, and then stay latched open until reset either physically, or by some kind of push-button trigger.

Without going into the tedious details*, I need to cut out a 300 watt inductive mains-powered water pump if it has been running for more than 10 minutes.

After a few phone calls to RS and others, it became clear I needed to make this out of two components, delayed-on timer and a latching relay. I found the timer at Cebek I-137 | 230Vac Delayed-On Timer Relay Module 2 to 45 Minute | Quasar UK

Now I just need the latching relay. So many choices, mind-boggled, not quite sure which one.

I'm in the UK, and this is a home hobby project, so suggestions of "just simply use this £395 PCL" wouldn't be so helpful!

And optionally, I'm also looking for a cheap mains-voltage buzzer which will just go "beep beep beep" when energized. Again, struggling to find that.

Thank you.

PS - yes, I realise this could be done with an Arduino, but time is short this month and I wouldn't trust myself interfacing the mains voltage part!)

(*OK, if you REALLY want to know the story behind why I want to do this, read this. It gets tedious... Looking for mains latching timeout relay to prevent water pump flooding | DIYnot Forums)

If you had two of those relay boards.. say A and B

Have mains power route through NC relay port on A before powering both A and B.

Now wire B up anyway you want.

Have both boards wired to same trigger signal.

Have B run for your duration, set A to run for one minute longer.

Once A activates, it will kick the relay from NC to NO thereby unplugging itself and B and then immediately reset back to A and B now having power again awaiting trigger.

That's an interesting and clever way of doing it, but seems a bit of a waste to have 2 boards, and takes it into the £40+ territory!
Just need a simple "trip" relay to be the second one, I think? Like an RCD or something..

Suggested adding a second board as you would be familiar with it, able to source it, and it would be rated for mains circuit your dealing with.

If that’s not going to work, well what starts the waterpump going in the first place.

It’s not supposed to run for more than 10minutes, but then what?

Is this a sump pump that will burn out if left running dry?
Will the pump normally shut off on its own within 10minutes?
How long does the pump need to be off after running for 10minutes.

Slumpert:
what starts the waterpump going in the first place.

A float switch detecting water is low in header tank

Slumpert:
It’s not supposed to run for more than 10minutes, but then what?

If it’s running for more than 10 minutes, it suggests either the float switch failed again, OR someone left a tap on or a pipe burst

Slumpert:
Is this a sump pump that will burn out if left running dry?

Well, if it keeps on pumping longer than 10 mins, SOMETHING is wrong!

Slumpert:
Will the pump normally shut off on its own within 10minutes?

It should shut off as soon as the header tank has refilled, which should take < 10 mins

Slumpert:
How long does the pump need to be off after running for 10minutes.

Until header tank starts draining again