Rake away. It will help thin out the bed, since you couldn't do this last year. Old leaves etc breed disease.

My best answer to voles is a cat.

A cat or cats. We have 3 outside cats and dead voles. My garden is 25x120' and no vole holes except when I uncovered the compost pile I saw a few and 1 vole. Two cats love to be in the garden with me. There are vole holes beyond our 2 acre property. Two cats roam all over so I suppose they watch our property closely. Picked up a "tail of guts" yesterday by the house, so the dog wouldn't eat them...lol.

I had a large garter snake the last two years......that oughta get um.

try working some egg shells or fine gravel into your soil. The voles do not like digging thru sharp stuff.

I have cats and garter snakes, and lots of little lizards but they eat bugs not voles. I like to make rock piles around my garden, they are both decorative and they serve as a habitat for snakes and lizards to live in, and escape from the cats when necessary.

If you are willing to create a new bed or if you ever decide you need to (strawberries should be rotated every three years I heard) you can line your new bed with hardware mesh before laying down soil that would keep them from digging under the plants then cover your strawberries with fencing from the top.