Well, I don't know how popular she is in UK, but in US I had a heck of a time finding "Venetia." I eventually found an old old old edition in a library 2 towns over. The book is basically falling apart at the seam, and the pages look yuck! (As you can tell, I really wanted to read it - and that's b/c I trust TDU's recs - thanks, Bel!)

Some of her books have newer editions, and bookstores sell about 10 titles. But I'm not sure I'd call her popular in US. I pretty much heard of her from my flist.