VM's coverage is not that patchy in Wirral there is a pattern to it. Their hub site for Wirral is in Bromborough so their network spreads out from there up the East side of the Wirral and also Willaston and Neston. They built the duct up to Heswall from Neston but then ran out of money. There is no Virgin Media coverage in Chester.
The OP isn't replying so I'm not sure if he's reading any of this anyway.