I’ve sold two Amazon stores through empire flippers but now have a software in the e-commerce space and through that I’ve met plenty of brokers and can put you in touch with some if you like.
I’ve sold an Amazon business and currently in the process of my second. Your yearly profit x3.5 plus the value of stock will be how the business is valued. The buyer will buy your business assets and not the limited company. Only if it’s £1.5m+ value, they will then buy the limited company itself from you.