The occult sourcebook / Nevill Drury and Gregory Tillett ; illustrated by Elizabeth Trafford Smith. (OCLC #4473790)

RDA 2.8.2 on Place of Publication says that if more that one place is listed on the source of information, only the first one is core, but other guidelines suggest more:

The LC-PCC PS says: for rare books, record all places of publication. For CIP cataloging, if the first place is not in the U.S., also record the first U.S. location (similar to AACR2).

The NLA PS says: for some publications (such as those from multinational publishers), record all places if the first one is not in Australia.

The D-A-CH says: if more than one place is listed on the resource, record all of them if possible.

The MLA BP says: if you are unsure which is the “true” place of publication, record them all. 

This (hybrid) record was created pre-RDA, so includes more than one place:

260 __ ǂa London ; ǂa Boston : ǂb Routledge &
    K. Paul, ǂc 1978.