help needed for strawberry plants

They'll have been molly coddled in the cold frame so maybe leave them in there for now but keep the lid open during the day to start hardening them off (and if they flower, it'll give access to the bees).  You might want to put them into pots at the same time so that when you do eventually move them into the big outdoors, their root disturbance should be minimal

I wouldn't have thought there was a problem leaving them in there, and you should get a lovely early crop of strawberries (if I recall in the Victorian Kitchen garden, they would put the strawberry plants in hot beds within a cold frame to do precisely that)  The cold frame can easily be netted off to stop the blackbirds from nicking the fruit 

You're right, Phil. Colframes aren't the best place for bringing on summer strawberries. They are super sensitive to damp which leads to fungus problems. Kept that lid open and netted as strawbs are naturally a cold hardy plant.