flybymike
I was a little surprised that any pilot of any experience wouldn't know what the fan lines meant (or where to find out - there's all sorts of interesting stuff on the legend of the quarter and half mil charts!!)
The point you make about crossing at 10 miles at 600ft is valid, but because Southend is primary only, they would have no way of knowing your level, unless you were talking to them. Under these circumstances and certain types of service, the ATCO would be duty bound to 'avoid' the unknown contact and possibly having to break off the ILS approach.
I struggle to see the logic of intentionally not using the services of a nearby ATC unit, particularly in a busy bit of sky, bounded to the east by a Danger Area, to the west and vertically by CAS. What's more, that service is free of charge!!