That bloody programme! I hate it - or I did; I will not watch it.
And look what has happened for you OP, it has reopened old wounds that will probably never fully heal anyway 
I was NOT adopted (I wish I had been)- but was taken away from my mother when I was three years old. I left behind my younger sister, and never saw her or my mother until I was 16. i only met my mother's father once, not long before he died. My mother had prevented it. He broke down when we met, which was sad.
That same year, a young man was looking for his birth family - and it turned out he was my (full) brother, who had come into the world, just as I was taken away from my mother (I apparently witnessed his birth at "home" weighing less than 2lb). He was in an incubator for 6 weeks and then went straight to his adoptive parents; my mother deliberated over the decision. Apparently.
My father to this day denies that he was ever told (my mother said she called him the day my brother was born, but he hung up on her after she told him about his son). And to THIS DAY like to cast doubt on my brother's paternity.
The big things is though - that NO-ONE told me that he even exisied! I of course agreed to meet him - and we got on very well. But I was effectively a conduit to his birth parents; mother agreed straight away - and he connected nicely with her and her other children (not me - I was left out of the first Christmas in case I "caused upset") - for a while.
My (his) father on the other hand - although I told him immediately - said that (my brother) could "call in if he was passing". He lived in the South France at the time! It took 12 years for them to get together, and that was all on my father. I hate him for it; and for things that he has said subsequently.
One of the main reasons we - or I at least - should have been told is, given how well we got on (at first), it does not bear thinking about should we have met NOT knowing that we were brother and sister (!)
As it was, he became unsettled with his girlfriends because he "wanted one like me" (?) I was married and early prregnant at the time we met, but had I not been and had met someone who was on the same wavelength ---- well........
Somebody - at some point - should have told me that he existed, and something of his story of coming into the world. Two - or more - wrongs don't make a right.
Both of my parents threw me away (and still do, given the chance) and yet went on to have children in other marriages. One of my mother's daughters died as an infant. As far as I am concerned, that is absolute justice.
A few years ago - I found out that I have another half-sister from my father's second marriage. I connected a little with the family of my ex-stepmother for a short time - but to be honest - it is just to bloody hard to be an outsider to so many different families.
I seriously do hate programmes like LLF for these and many other reasons - let alone, making entertainmant out of heartbreak really REALLY pisses me off.