to think that this is real CFery?!

I'd not be happy at all, but, did he charge you for using his pub for your party? If not, then he might assume ( wrongly ) it's okay because you havnt paid him anything

I’d screen grab the Fb post and send it to the llady saying “I think there may be some crossed wires? My understanding was I was paying for x activity for my birthday celebration so have invited family and friends to take part. I didn’t want to prevent regulars coming but wasn’t anticipating my birthday activity being advertised as open for all.”

see what her response is and go from there.

Dear LL - just heard through the grapevine that you're advertising an event at the pub on X date. I guess you must have double booked the venue or I got the wrong date? But no worries - I'm sure I can find another venue. Hope your evening guess well.

Cancel, book elsewhere and invite those who would be at the pub anyway so they will also not be there!

Cancel and book elsewhere

Very CF
Hope it works out!

How many people were you thinking (as an estimate) would come?
if not crazy amounts I would just book somewhere else, private room and catering.

I think you need to speak to the LLady today. It doesn’t matter whether it’s her fault or LLord, it’s their business so both need to be responsible.
Say that the whole thing is getting out of hand and your plan has been totally misunderstood and you are mortified and they will need to pay for half of the evening if everyone and his wife are turning up (obviously will mean they make a lot more on drinks etc).
It needs sorting today otherwise this will be eating you up and will ruin your evening.

Although 9 is late enough as it is I'd push the start time back by half an hour, or even an hour if the start time is earlier but don't tell LLord. Anyone who turns up especially can get annoyed that it's not starting when advertised and he can't do anything about it.

I think you should speak to the LLady and explain what has happened.

On a practical note, ask her to put ‘Reserved’ signs on the tables near the entertainment/buffet. Or ‘reserved from 9pm’ if you’re starting a bit later. And make sure any food isn’t put out until you are ready for it.

I too think you're going to have to make time to phone them op

I can kind of see it - you did say you were fine for anyone to join.

however the landlady said it is quiet after 9. So publicising it is a bit much! If when you get there it is not quiet after 9 then I would be taking it up with them and showing them print outs of the Facebook post.

Comment on the Facebook post?
If you were that bothered you would speak to them before Saturday? Bit strange

And completely different for random strangers sorry

It is a big deal though-it’s one thing for people you would invite anyway and random strangers off Facebook

This is already outing so surely you can tell us what it is?

Context would be helpful as pp said it it's karaoke then I don't think its a big deal.

I’d be changing location and telling him why

Have you changed the entertainment and it’s actually karaoke you are putting on and that’s what the LL has advertised? To be honest I don’t really see it as hugely cheeky to announce there will be karaoke available on Saturday if you’ve already said you’re happy for others to join in but would make sure your own guests got priority if it did become busy. Whether it was a proper karaoke set up or just a mate with a small karaoke machine would also have some bearing too.

2reefsin30knots The OP discussed the party with the landlady who was the one who told them that the pub would be quiet then anyway and was apparently fine with the arrangement. If the landlord didn't like it he could have contacted OP and asked to piggyback on the party not just announce it on Facebook with no discussion.

OP if I went to a pub for the entertainment and found out it was for someone's birthday party I would be horribly embarrassed and would feel like a gatecrasher. I wouldn't be back to that pub for a long time. This could backfire on the pub badly.

I disagree that OP is in any way exploiting the pub owners btw. There wasn't a private room to book and she had agreed it with the landlady. The whole point was that there were usually only people there she'd be happy to invite. Landlady is getting a bit more custom than usual from this so a benefit rather than a nuisance for her. The odd stranger dropping in wouldn't cause a problem, but publicising an event for all comers is a different matter entirely.

You haven’t booked the pub though, you just arranged a gathering at the pub and asked the landlord if you could bring entertainment in to the pub which is a bit weird in itself so I don’t think you can complain.
he probably wanted to advertise it so that if there were other people wanting to go to the pub they didn’t feel like they were crashing a private party.

Are you paying the pub anything for agreeing to hold your party there OP? Paying the bar staff, covering any costs incurred (eg electricity if your entertainer requires this)?

Because you're treating this as if it were a private party - which it isn't! If you'd had to book a private room, you'd have had to cover all these costs.

The LL is simply capitalising on an opportunity - he's running a business not a charity.

I'd be grateful that the landlord has agreed to host your 'do' for free if I were you!

Absolutely cancel. And consider whether that's a pub you want to frequent in the future. If I were the friend who offered to provide the "bingo" for you and your friendship group I'd be miffed at being exploited by the LL and potentially the entire neighbourhood!

Personally, I'd cancel.

If you still want to go ahead you need to contact the pub and get it resolved. Waiting until you can speak in person is just silly.

At the moment you aren't having a birthday party, you are paying to promote their pub and feed their customers.

This I"m afraid. I hope you have a greatvtime anyway.