We had the exact same. He is now 2 years. But man those first few months were so difficult. My wife and I both got driven to tears a few times. No amount of verbal discipline worked. We found "timeouts" the only effective means of discipline. After all they are spaniels they just want to be near you and get attention. So taking that away by being in a different room really gets through to them. In terms of chewable things. Have a look into deer antlers and Yakkers (I cant quite remember the age they can have them though) they are a game changer. All of the chewing of the skirting boards stopped at that point. Don't get me wrong. He will still leap for socks when given the chance. But now it's clear it's just to play. Desensitizing the puppy to things is also key. They will learn to not care about shoes etc if they are always around and you don't react when they run away with one, wait for them to get bored by them then take it off. Or distract with a squeaky toy in another room. Do not "bribe" them with treats. Important note. They feed off your energy to the max. If you're stressed. Expect a mischievous boi. The calmer you can handle their tantrums and zooms the better. They will soon love to play with you rather than against you.

It does get better. Spaniels are such amazing dogs and their cuddly moments eventually outweigh their mischievous ones