Not many will have predicted Mikey Johnston to have the impact he’s having at West Brom when joining from Celtic on loan – and Carlton Palmer discusses how much a permanent move would cost. Six-time Ireland star Johnston, 24, only managed 12 outings for Celtic during the first half of the season and that saw Brendan Rodgers sanction a loan exit in January – moving to play-off hopefuls West Brom. The winger has been superb. While he has also been a player with plenty of promise and certainly gifted technically – his end product has come on this season. In nine games for West Brom, he’s scored s…