Ok, Tramp, then your equipment is obviously all working, and you’ve also found and scanned Astra2, so it’s just a matter of sorting out this particular problem!
I got only the Lidl receiver, (and am using my existing Sky minidish). Knowing more about your antenna would help. What size dish (cm)? What lnb arrangement (one, or more than one on adjustable brackets, or “monobloc”- ie - 2 or more horns but only 1 output)?
(If I’m ok with just a 43 cm minidish , any dish you got must be bigger, so you should also be ok!).
(In what follows, if using a multi-lnb dish, please use the same lnb each time, and select satellite by re-positioning dish. I realise that's a pain, especially if going up and down a ladder, but it should give a "clearer" result.
Also, when positioning on a particular satellite, to find max signal, remember to move dish up and down, as well as from side to side!).
Use Astra1 as “reference” (since that’s “working”). Do you get all channels ok, without any “breaking up”? (if not, then you’ll have trouble with Astra2, since it transmits at slightly lower power!).
To receive properly, “signal quality” (NOT strength!) should be around 38% or higher, although some channels might be ok below this. If there’s problems with some Astra1 channels, look at signal quality on them. Otherwise, what is “typical” Astra1 quality?
Assuming Astra1 is ok, now go for Hotbird, which you find by rotating dish approx 5 degrees to right (looking from behind dish!). Adjust dish to maximise signal strength - it’s noticeably lower than Astra1 – and check you’ve really got Hotbird by going through preset channels list in receiver.
Are all Hotbird channels ok, with adequate reception and quality? If so, then you should also be ok with Astra2, which transmits with a strength somewhere between Astra1 and Hotbird (if Hotbird isn’t ok, then you may have an antenna problem!).
So, assuming Hotbird was ok, now put antenna back on Astra2. First check you can get some channels, then look at signal quality on the BBC channels; is it below the required 38%? If so, then almost certainly something is blocking the line-of-sight signal path between Astra2 and your dish, so check this! Remember, the “signal beam” goes upwards at approx 26 degrees (even though the dish “seems” to be pointing straight forward!). Growing trees are often the culprit.
This should all work! If not, then at least going through above steps should provide specific info for further diagnosis.
PS, I've just been looking at the most recent Lidl "sat package" offer - which I assume you got - and it seems they give you a 60cm dish with monobloc lnb. This will simultaneously get Astra1 and Hotbird, on a fixed (not motorised!) dish. But, you can't then also get Astra2! If you point dish at Astra 2, you'll get it, but then will get neither Astra1 nor Hotbird (oh dear!).
The easiest solution - if you're in a "reasonable" Freeview reception area (look at local roof aerials, and try out a friendly neighbour's Freeview box on your existing tv aerial If this works, just buy a (decent quality, not cheapest!) Freeview receiver, and you'll get the BBC channels that way (plus the BBC digital text services, which are also on Astra 2 satellite, but the Lidl receiver can't decode them!). Freeview will also give you more "good" channels, such as E4, ITV2, etc, which are subscription only on Sky.
Then, you'll get the "Best Deal", with all Free Astra1 and Hotbird and Freeview channels!
If you can't easily get Freeview, then you might consider putting a diseqc motor on the 60cm dish, to move it between Astra1/Hotbird and Astra2, I think they're around £50 upwards.