Parkfell's advice is good advice. I found the following information from the CAA website regarding visual requirements for a Class 1 and Class 2 medical:
MED.B.070 Visual System
(b) Visual acuity
(1) For a class 1 medical certificate:
(i) Distant visual acuity, with or without correction, shall be 6/9 (0,7) or better in each eye separately and visual acuity with both eyes shall be 6/6 (1,0) or better.
(ii) At the initial examination, applicants with substandard vision in one eye shall be assessed as unfit.
(iii) At revalidation and renewal examinations, notwithstanding point (b)(1)(i), applicants with acquired substandard vision in one eye or acquired monocularity shall be referred to the medical assessor of the licensing authority and may be assessed as fit subject to a satisfactory ophthalmological evaluation.
The following
link has guidance regarding amblyopia related to a class 2 medical.
From that it would suggest that the monocularity was the reason for the failure of the class 1 medical initial issue.
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