I am assuming that the Spax listed are the standard M3W item? Spax adjustable shocks are available from some Morgan dealers such as Rutters for £217.10 + VAT each. They are a bit of a step up from the standard Spax item but not great and also it's not possible to get them serviced or repaired, unlike Ohlin's and ATR's (and maybe Mshock?).
The Spax shock listed above for £205 are the adjustible version and for a pair