Have to take a tyre off my Model 607, the tyres are straight sided and the rims have a feivable outer ring hekd by a single nut. Any tips before I start tsking this apart? Assume the tyre innervtube must be fully deflated first!

No magic involved. Safely block the axle high enough off of the ground for the tire to clear the ground when being removed. Deflate the inner tube. Pry outside tire casing bead back from outside retaining ring far enough for retaining ring clearance. Remove outside retaining ring. remove valve stem cover and retaining nut. Pull outside tire casing bead clear of rim. Disengage valve stem from its hole in the wood felloe. Pull inner tube free from tire casing. Pull tire casing from rim. Re-assembly requires care in preventing wrinkles in the inner tube. Using talcum powder to help prevent wrinkles and re-inflating the tire a couple of times helps eliminate the wrinkles in the inner tube.