It's a permanent fix but it's easy to extend the depth of the Scalextric guide to suit a wood track.
Cut a strip of thin clear plastic from blister packaging or similar about 7/7.5mm deep and as long as twice the guide length of a Slot.It deep wood guide with a couple of extra mm added on for good measure (obviously if I wasn't at work and had one to hand, you'd have a real measurement there. From memory maybe 50-55mm or so).
Fold in half and cross-hatch score the inside. Cross-hatch score the Scalextric guide. Superglue the sides of the guide and fold the plastic around it with the inside of the fold at the tip of the guide, grip tight with pliers until the glues dry. Sprinkle some baking soda on it to accelerate the superglue if needed.
Don't glue the "tail" of the plastic where it overhangs the guide, it works better if allowed to flex slightly and conform to the slot in tight corners.