L'Estrange spent most of his adult life immersed in the politics of the day, leading to experiences ranging from a term in prison to a Restoration propagandist to the dual roles of Surveyor of the Imprimery (printing) and Licenser of the Press. In these latter roles (which span the 1677 publication date cited for the
...Toad pamphlet) he was described as a zealous and effective watchdog patrolling the English press - something which apparently garnered him even more foes than his own political actions and writings had accreted.
I mention this context because ...
A circa 500-page retrospective on L'Estrange by a George Kitchin (
Sir Roger L'Estrange; a contribution to the history of the press in the seventeenth century, 1913) is available online (if you can tolerate a 30-some megabyte download in PDF format) at:
https://archive.org/details/sirrogerlestrang00kitcrich
This book ostensibly provides listings for all L'Estrange's publications. It also provides a gruesomely detailed history of the conflicts, intrigues, and outright shenanigans involving L'Estrange and publishing / publications.
There is no mention (in the text, nor in the listings) of any publication with the title you cited. Neither can I find anything from 1677 that seems to be a candidate 'hit'.
However ... I noticed the book mentions L'Estrange was the victim of 'fake pamphleteering' (being accused of authoring questionable publications) during this period.
All this makes me wonder two things:
(1) Was the ...Toad pamphlet not a news item, but rather some sort of veiled / allusive political tract whose metaphorical references are now lost on us?
(2) Was the ...Toad pamphlet one of the pseudo-L'Estrange publications (again, metaphorical / political) against which he had to defend himself?