Can I use plural form of a nous as if it is a singular? [duplicate]
Solution 1:
There is much discussion in other questions, referenced in @Rosie F’s comment, about the subject-verb agreement in sentences beginning with “There is.”
But “There is caps that suits . . .” is also a question of the agreement between “caps” and “suits,” which is clearly ungrammatical.
Florence Nightingale is quoting someone she presents here as speaking uneducated English. Whether she is inventing the details of this dialog we don’t know. I also don’t know whether this kind of phrasing was, in the mid-19th century, typical of uneducated women in Britain, or perhaps of Cockney dialect.