once the topic was drug away from a rack top bag , to a saddle bag, then the vote for a Super C
with its easily operated side release Buckles Vs, the leather-strap and buckle of the traditional bags ..
can be taken ..

though following the prior link though it lacks side pockets, there is a CarraDry Saddle Bag as well

One wonder if there are UK resellers discounting SRP, As typically when you buy direct from a Producer
who also sells thru dealers , they support their dealers businesses by selling at SRP,
and wholesaling to shops for less ,
and they can choose what margin, over cost they are willing to take.