I don't know about englands soaring, but I assume it's like german; ie shabby at best (one month a year). Those guys have to visit Africa or America to do long soars. Anyhow, if there is soaring in england cost will be much MUCH less when you solo unless there is some weird queen tax or such. (LOL)
My previous club is probably an exception, but cost was following; monthly club membership (~60$), yearly soaring membership (~200ish IIRC), plus towing cost (1500agl for about 15$). No instructor fees. No time in glider fees. If club is running low on cost, they may request extra money, but it's still less than others.
Anyhow, more you fly, less the cost. So if I go for a 5 hour solo ride (assuming I'm only guy signed up for that tail), that's a LOT cheaper than 100$+ a hour in Cessna.
Find what kind of soaring there is to be had; aka thermals. No thermals (ridge soaring etc), is a deal breaker IMHO. Find costs to solo. Find total cost and do some math.