Although no dates have been found in any of the Pocket Love Library or Pocket Romance Library issues indexed so far, we can use the cover price values to estimate when the issues were published.
Various issues of Pocket Love Library have been identified, none after #23 so far. Issues up to #14 have a 1/- cover price. Starting at #17, the issues have a 6p cover price. So it seems reasonable to assume that somewhere between #14-#17 was when Decimal Day (https://en.wikipedia.org/wiki/Decimal_Day
) occurred. This places the Pocket Love Library series around 1970-1971.
Various issues of Pocket Romance Library have been identified, none before #30 so far. The cover prices gradually rise on the covers of that title from 6p to 12p.
The actual number switch point between the titles requires further research.
More issues may remain to be documented.