Surely the same amount of work is involved regardless of property price?
The truth is, regardless of how simple a matter may seem, the same amount of due diligence and compliance is required of conveyancers by UK Government.
Even a simple matter, which you think can easily be dealt with, needs a paper file to be opened, due diligence, up to date client ID, AML checks, source of funds compliance and so on. This applies even if you are an existing client. This admin mounts up and results in the fees quoted.
Conveyancers are NOT permitted to dispense with opening a file or with due-diligence. Regulations bind conveyancers. We have no choice.
It is also worth noting that your law firm must have Professional Indemnity Insurance (PII). Every transaction affects the firm's PII. A property with a higher value will require a higher contribution. This accounts for the sliding fee scale.
HM Land Registry fees also change depending on property price.
Higher Value = Higher Fee.