Raise the engine covers.
Remove the centre support the part that carries the gear selector,put the gear selector to one side you will have enough space. Unhook the wiring carefully and remove the engine bay temp sensor. Unplug the wiring to the BACS valve lets call this the ISCValve from now on.
At the front the ISCV has two small coolant pipes attached , clamp these off and unhook them.
Unhook the plug from the ISCV and remove the front air pipe. Check the pipe for damage.
At the rear of the engine loosen the ATX cable two bolts and then remove the rear covevr from the rear bulkhead.undo the duct work from the throttle body to the main intake flexy duct, careful here as they bake under there and it is prone to become brittle so treat it gently, loosen the whole duct assembly that should give you the wiggle room you need .Check the elbows for signs of splits leakage etc replace if required, these are not available as far as I can find so you will need a couple of 9 mm nylon elbows fix these in with PU adhesive not silicon sealant on re assembly.
On the nearside there is a small bore pipe that goes from the evap canister to the engine inlet remove this, next to the throttle quadrant you will see a single wire unplug this too if you cannot release the plug cut the single wire leaving yourself enough to remake the joint, release the throttle cable.
On the off side undo the plug to the throttle Potentiometer ( three wire plug),there may be some others I have missed so have a check over for items attached to that plenum. remove the bolts holding the plenum to the inlet manifold and the support bolts dotted about.
You should now be able to lift the plenum off the inlet take care here and bung the inlet with pieces of cloth in case anything drops in while you are working on the rocker cover.
On the top of the cover you will see a small valve with a pipe coming from it , this is a push fit into the cover remove this.
Check it for operation by sucking and blowing this is part of the breather system and is a one way valve wash this in petrol.
Rocker cover
Remove all the bolts from the flange off the rocker cover and remove it. turn the rocker cover over and you will see a baffle plate held down with a number of cross head screws try and get a look down here to check for any blockages very unlikely but while your there etc. Check the rubber elbows on the breathers for signs of perishing if suspect change them.
Remember the valve in the R/Cover check the pipe work that leads from that valve to the Y branch and back to the main inlet duct any sign of damage here change them.
As an aside these engines tend to suffer with idle problems after a while so you may want to strip down the ISCV at the same time and give it a clean along with the throttle butterfly at the other end of the plenum.
Remove the old gaskets and clean all the surfaces ensuring they are nice and clean.
Reassembly.
The following is how I approach this type of gasket.
Using a gasket varnish like Wellseal and a small brush paint the recess where the old gasket sat, allow it to tack slightly before fitting the new gasket into it.
Put it to one side.
Paint the surface of the head rocker flange and the cam semi circles with an even coat of Wellseal. In the corners of the semi circle wipe a bit of the varnish away where it meets the flat plane of the flange and place some silicone gasket sealant four decent blobs, working fairly quickly, paint the face of the new gasket with the varnish and reassemble. check the gasket is fitted correctly and then tighten down the rocker cover working from the middle out opposites at a time evenly to 7nm.
Replace the breather hoses if removed.
Plenum.
Use the same process with the gasket varnish buttering all the faces of the plenum gasket and there mating faces and allow it to tack off.
Refit the plenum tighten the manifold bolts to about 2nm. Now refit all the parts you removed.
Finally wash the oil filler cap in petrol.
Don`t forget to rejoin the idle switch wire if you cut it.
Think that is about it probably missed loads but they will be obvious as you work through it.
Good luck.
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