Right, I realise I've been completely lazy about updating. In short, I've been driving madams MX5 for the past 2 weeks and have largely ignored the 500.
I did however order the goodies required for making the drop links from McGill motorsports on eBay. Complete list of parts and prices below if anyone else wants to replicate the experiment:
180851727933 M10 x 1.5 mm Half Nuts / Lock Nuts Right Hand - Pack of 1014.75 GBP4.75 GBP
160561203053 M10 x 1.5 mm Half Nuts left hand pack of 1014.75 GBP4.75 GBP
380444144576 Sealing Boot for M10 and M12 Male and Female rose joint, rod end Dust Cover43.90 GBP15.60 GBP
160465862236 M10 Male Left Hand thread HIGH PERFORMANCE Rose Joint27.25 GBP14.50 GBP
180544075604 M10 Male Right Hand thread HIGH PERFORMANCE Rose Joint27.25 GBP14.50 GBP
180790423987 Turnbuckle M10 Link. Adjustable from 300 mm to 340 mm26.70 GBP13.40 GBP
Subtotal: £67.50 GBP
Added to that will be a handful of bolts, washers and spacers so call it £75 in total. The Fiat originals are £36.60 for a pair, which makes my little experiment about twice as expensive as just buying a set of droplinks but it keeps me amused.
Those of you with too much time on their hands (yes Maxi, I'm looking at you) will have noticed that the turnbuckle is adjustable from 300mm to 340mm while the Fiat factory ones are 290mm non adjustable. The reason I chose these is because I'm planning on a 30mm drop which means that ideally the droplinks have to be 30mm larger than the standard which means 320mm to keep the arb at the correct height to be properly effective.