It does look like a citrus to me. Take off one of the damaged leaves, crush it in your fingers and have a sniff. Citrus will smell of lemon, orange or lime but a bay will smell quite different and distinctive. A magnolia will produce no real smell other than of crushed leaf. If a citrus, I would get some specialised citrus food which comes in 'summer' and 'winter' feed types. You'll also need to give citrus protection from the cold over winter. I wouldn't feed a magnolia or bay at this time of the year as you don't want new growth which could get damaged by frost.
A trowel in the hand is worth a thousand lost under a bush.
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