Can anyone help me work out the syns in M&S king prawns with a basil pesto dressing? I think they are new.

Per 100g:
Cals 141
Fat 8.1g
Of which saturates 1.2g
Carbs 0.5g
Of which sugars 0.3g
Fibre <0.5g
Protein 16.4g

The pack contained 140g and I ate the lot. Prawns were 78% of the pack. Iím hoping they are no more than 4 syns but am panicking now.

Thanks you in advance.