No point in spraying with a fungal spray ... I can't see any fungus. That looks to me like damage from the winter weather.
I'd repot the bay (John Innes No 3 loam with a generous helping of added horticultural grit) and later in the spring spray the leaves with dilute seaweed fertiliser. The worst damaged leaves will drop but as long as the branches are ok they'll produce new leaves in the spring.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Even if it had a fungal infection I'd not recommend spraying with Roseclear - it's for ornamental plants only, and you wouldn't want to ingest it... but I'm with Dove, if you're gardening in the British Isles that's almost certainly damage from cold winds. Monty Don showed what had happened to his bay trees on Gardener's World last night - they looked very like yours.
Since 2019 I've lived in east Clare, in the west of Ireland.
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I'd repot the bay (John Innes No 3 loam with a generous helping of added horticultural grit) and later in the spring spray the leaves with dilute seaweed fertiliser. The worst damaged leaves will drop but as long as the branches are ok they'll produce new leaves in the spring.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.