It’s a definite no. We know of some conversion companies asking for 25% of the contract price before starting work. Taking deposits from home owners is a complex legal arrangement. If you are asked for a deposit, you need to know the terms of the deposit. IE, is it refundable, at what stage is it refundable, when can I cancel the agreement and how long does it take to receive my refunded deposit. Simple, don’t pay a deposit! Pay when works commence.