pastry freezes fine - look at all the frozen pastry good you can buy in the supermarket!!

try things like sausage rolls (small) made at home. ummm, DH takes small packs of fruit (two fruits/fruit salad etc), salads, cold snags or rissoles. cheese and kabana with healthy crackers.

during winter, you can send him with a hot lunch. we make food in the slow cooker, freeze it in the disposable oven trays, then DH heats it for an hour or so in a small portable oven (it was $37 from d!ck smith)

it's harder for me to suggest stuff as DH essentially lives in his truck so has a large fridge, and can stop and actually cook using gas cookers...