In this case, the brown tissue is not covering the leaves; it is the leaf tissue itself that has died due to environmental conditions (not a pest or disease). This is either old winterburn (winter-damaged foliage from this past winter that hasn't shed yet) or scorch, which can occur from conditions like under-watering. Over-watering can also damage leaves, but when that happens it instead usually causes entire branches to wilt and turn a sickly yellow-olive-green color before any parts of the leaves turn brown and brittle.

Stone mulches can add to plant stress, especially if the plants are near another source of heat, like a wall, solid fence, or paved areas that reflect or radiate warmth and which reduce air circulation. This plant appears to be planted close to a wall, so that might be a contributing factor. Stone mulches also make it hard to monitor plants for watering needs, since that should involve feeling the soil moisture level about six inches deep into the root zone. (If somewhat dry to the touch at that depth, a thorough watering is likely needed. If damp when checked, watering probably isn't needed.)

Was the root ball on the cherrylaurel loosened-up well upon planting? (If it was potted, were the roots disentangled, and if it was burlapped, was the burlap and any twine or wire removed?) If not, that can make watering and checking for moisture accurately more difficult, and will also hamper establishment.

The minor amount of leaf yellowing and shedding at the base of the plant is normal and to be expected after transplanting. (Evergreens do normally shed some of their oldest leaves each year, often in spring.)

There is nothing you can do about the already-brown leaves (injured leaves cannot heal), and they will fall off on their own in time as new growth replaces them. Keep checking the plant regularly (perhaps once or twice a week in dry weather, depending on how recently they were planted) for watering needs.

Miri