the frog looks right but the scratchings on the base look all wrong. A few things to consider:-
1) Signed "J. Ditchfield", numbered and Glasform on base means John designed and made the piece.
2) Signed and Glasform means John designed the piece but it was made by one of his colleagues.
3) Glasform alone means it was designed by a Glasform colleague and made by a colleague.
4) NO GLASFORM either means pre-1982 at another works or NOT John's.
Since this sort of frog design was not made before Glasform, then if no Glasform on base, it is possible that it is a similar design by someone else. Please note, that without attributing any blame or responsibility, John did have an employee leave and start making "similar designs".
Hope this helps,