Urgent London question- please help !!!

[FoodieToo]

Hello ! We are over in London from Dublin for a match and musicals . We have decided it’s a waste not to see two musicals so booked to see Matilda again today !!!!
Anyway it’s leaving us short of time to get to Gatwick.
Here is my question. We have return tickets from Blackfriars BUT we now want to get on at London Bridge .
Will the ONLY let you through at the start station or will we be able to get on at a later stop ?? Technically we are using less rail time !!!
Massive thanks for any help !!

You'll be ok. Go through the manned barrier if your tickets don't work.

Should be fine, don’t worry. Show an actual person if for some reason it doesn’t work at the barrier.

Both stations are in Zone 1, so you shouldn't have an issue. But as PP said, go to the manned barrier for clarification

Just show the tickets to the person on the barrier, it's fine to get on St a later stop.

Worse case scenario tap in with your credit/debit card.

It is fine.

Totally fine

OP, I've done this many times and agree with PPs, go to a manned (personed?) barrier.

It will be fine. Even through the barrier I expect.

Most tickets will let you on at any main terminal but you must do an unbroken journey from that point, ie no hopping on and off trains once you're on.

Getting on a bit further up the line should be no problem at all if your return ticket is being scanned for the first time.

Thank you all SO much , we will just chance it and if a person is there we I’ll ask them !!
Really appreciate the quick and useful help !