Here is the DVDBeaver review for
Asylum Asylum Blu-ray - Britt Ekland
The SS is a compromised transfer but it's still the best out there. There may not be better elements? I love the movie so I'd still rather have it in my collection even if it is not reference level... at least until someone improves on it.
The House That Dripped Blood appears to be better although the reviewer complains the black levels are a little too light.
The House That Dripped Blood Blu-ray - Peter Cushing