We don't have seed allergies, so you'd need to double check on that, but we use Lea & Perrins.
Ingredients
Distilled white vinegar, anchovies, garlic, molasses, onions, salt, sugar, water, chili pepper extract, cloves, natural flavorings, tamarind extract
If you prefer something without anchovies, you might consider Pickapeppa Sauce - it has a similar flavor profile and I think would substitute well for Worchestershire for most uses. Again, you'd have to double check WRT seeds.