Can anybody identify from which order these nuns are? Picture taken Eastbourne about 1900.
The order I believe it is the order of Grey Nuns (of the Sacred Heart).

Here is a US branch with an image with a similar headpiece.

Here are a few different orders but the leftmost is a Grey Nun with a heart-shaped headpiece.

This is the original posting of that image but there aren't any details besides those given by OP.



@MattGutting found a nun who disagrees with me (I am not certain in my answer so it is definitely possible). She says:


  Def not Gray Nuns. They have more of a widow's peak looking thing. Could be Sisters of Christian Charity of St Elizabeth w/ modified neck piece. They may be an order unique to the UK, however. The ones that tend to have the "heart" facepiece are usually some form of "Charity" nun.