Can anyone lend me some advice?
I've built up my engine and attached my carbs,But when it came to attaching the linkage that I bought it doesn't seem to fit. Can anyone tell me where I'm going wrong? Do I need a different linkage?

You will need to swap around, alter or change to linkage connectors on the carburettor spindles as the centre linkage pulls into the centre of the engine other linkages work the carb butterflies the same was synchronised. Firms like eurocarb and webcon sell the throttle linkage plater.

Eurocarb is my go to place for rods. Never come across a case I couldn`t knock up the exact lengths need. Remember many linkage rods have left and right hand threads.

i can do you a new complete kit for £60 posted 

had these kits fitted for 10 years works great

Ive got the same as Richard, works well

[Important....]

The CSP linkage is quite robust being designed to suit 6mm ball ends. Eurocarb is my go to place for rods & all things carb related. You never seem to get two setups that are happy with same settings. I have both left & right hand thread thread taps so for me it`s just a case of getting rods I know are longer than needed and then I can extend the threaded section of each rod and/or chop off the "over length. If you fit the swivel type action stick to this procedure which assumes the rocker gap and ignition timing are what your engine likes. Factory ignition timing is just a ball park. With the throttle cable fully disconnected and the swivel in the carb idle position........
When you are sure that rocker gaps and ignition timing is ok wind out the carb mixture screw 2 turns from fully in. Dab a bit of paint, tippex or marker pen on each screw so you can be sure of what is a 1/4 turn half turn etc. Unscrew the "idle screws to be sure the throttle butterfly assemble is in the fully closed position. Rotate the throttle linkage to fully open and mark the carb where this point is. I have come across so many twin set ups where the throttles are not able to rotate to fully open. Clamp accel` cable to centre spindle with spindle fully rotated anticlockwise. (There should be a stop method). Leave rods disconnected. Adjust each mixture screw until the engine settles to a reasonably even idle. (Will need idle screws wound in a bit but just a tad at first). If you have access to an air flow meter great use it to match air flow on each side also using mixture screw to get a completely stable tickover. If you havn`t access to an air flow device use a piece of tube down the carb throat and listen. This is quite accurate when you have a bit of practice. Match the hiss level both sides. (I use the flexible ali` tubing that type 1 engines have for air to carb and bend it to 90 degrees to fit flow meter to.
As a guide I have found that with a settled in system the ICT`s will draw in at a meter reading of 7. This on many engines but don`t take this as what you will get.
The two rods......  They are threaded right hand and left so that in order to adjust length you just turn the rod one way or another. Check again the throttle stops are fully home touching the idle adjust screws. Fit one rod and then the second ensuring you are not opening either carb throttle. Check closely you have full throttle opening. If so alls well.    Run the buggy on the road for at least 50 miles then when you get back quickly whilst engine is hot check air flows match. Important.... People argue with me over this next statement but it is 100% correct. It takes a minimum of 20 minutes running from cold after an overnight in garage or outside to get it properly warmed up. This is why during an mot the tester will start engine, rev it up and then let it idle for a while before looking for "smoke" or doing emissions checks when needed.