Afternoon, Jack. can't have you being confused, can we? Here is the full sequence:
On Angel Mountain (Part One), Greencroft Books 2001. ISBN
9780905559803. A5 paperback, 328 pp, 6.99.
(also Corgi edition 2006)
House of Angels (Part Two), Greencroft Books 2002. ISBN 9780905559810.
A5 paperback, 432 pp, 7.99. (also Corgi edition 2006)
Dark Angel (Part Three), Greencroft Books 2003. ISBN 9780905559827.
A5 paperback, 432 pp, 8.50. (also Corgi edition 2007)
Rebecca and the Angels (Part Four), Greencroft Books 2004. ISBN
9780905559834. A5 paperback, 432 pp, 8.50.
Flying with Angels (Part Five), Greencroft Books, 2005, ISBN
9780905559841. A5 paperback, 400 pp, 7.99.
Guardian Angel (Part Six), Greencroft Books, 2008, ISBN 9780905559865.
A5 paperback, 256 pp, 6.99.
Sacrifice (Part Seven), Greencroft Books, 2009, ISBN 9780905559902. A5
paperback, 352 pp, 7.99.
Conspiracy of Angels (Part Eight), Greencroft Books, 2012, ISBN
9780905559933. A5 paperback, 352 pp, 7.99.
The first three volumes were also published by Corgi, and they may still be available in the US through Amazon and other sources. Watch this space -- Kindle and other Ebook versions will follow shortly.
I agree with you about Downton Abbey and Upstairs Downstairs (the new series started last night) -- I am a great fan of both! Cleverly written and beautifully produced -- perfect Sunday evening viewing. But they just aren't WELSH!! In a perfect world it would be nice to see BBC Wales doing series such as those AND some decent drama set in Wales, and coming from Wales.