I emailed shell on Friday and recieved this confirmation email back:
Dear Brian,
Thank you for contacting Shell UK.
Due to unforeseeable circumstances, we are currently experiencing a temporary disruption in the supply of Shell V-Power gasoline. We are doing all we can to resume supply of Shell V-Power gasoline, and we apologise for any inconvenience caused.
If you require any further information or assistance do not hesitate to contact our customer service centre at 08007318888.
Yours sincerely,
Ria
Shell Customer Service Centre
Rowlandsway House
Wythenshawe
M22 5SB
Shell U.K. Oil Products Limited is a separate limited company, which acts as agent and manager of the oil products business of Shell U.K. Limited.
Shell U.K. Oil Products Limited Registered office: Shell Centre, London SE1 7NA
Registered in England: No. 3625633
It seems that this is a national problem and they avoided the question of "how long will this last".