Feel free to just put a Dibs on them if you really want them and agree to the payment terms.
Then follow up with a PM to the seller. This will "put you in line/queue" to buy them.
Otherwise people might think that you're "just browsing," allowing someone else time to put a Dibs before you.
I'm your PM you can say that you are "ready to buy, but I'm also looking at another offer and will go with whoever closes the deal first....." or whatever your situation is.
Bring upfront and letting everyone know what you plan to do in your PM will help both parties understand your situation.
Vacation was indeed a lot of fun! And yes, these are still available. Although I will be flying to London on Thursday so once again, a limited window; back mid Feb.