Let me get this:
You had a haflinger mare transported from the netherlands, to the UK? Or someone else did, and that mare is yours now? I guess the second. Now you want to know where she came from, so you can find out what her pedigree is because it sais "unknown" in the passport?
The mare has a brand, so she has a pedigree. She should be a older horse, because we don't use brands for many years now. So that age of 25, could absolutely be correct.
The passport details are:
Name: Lientje 0921069
Identification no 528023-200921069
Microchip no 967000001251546/528210000097508
Validated on 30/04/2009
O/B: Fair 6 5469 KD Erp (Keldonk) Tel 0031 (0) 413 209 042 Mobile 0031 (0) 6 4270 0062
Registered with Irishcob @ planet.nl
There is a bar chart with no 967000001251546
This is the microchip number
Her passport was registered by Hans Joosten. So I would think, the contactinformation in the passport, is his.
About the email you got. That is just that she thinks your mare could be from the St-line, because of your mares looks and age. But offcourse she could not know that for sure.
So, did you try calling the phonenumber in the passport? That would be 0031413 209 042, or 003164270 0062 on cellphone. That is including areacode, so just can just type this numbers and press call That would definately be my first clue! However, this man is the owner in 2009, he could well not be the breeder. You should ask him that if you can get ahold of him. Because the breeder is the one that knows her pedigree.