Go to the fuse box in the engine bay and remove the yellow [20 Amp] fuse, identified as EMI on the fuse box cover. Turn the engine over for a couple of turns, this will cut the fuel and remove any fuel pressure in the lines.
Place a tray under the battery area to catch any fuel spillage when removing the filter.
To change the fuel filter, remove the battery [negative terminal off first]. You will see the battery tray, in the middle are two small nuts, 10 mm socket, undo these to release the washer bottle. Then undo the four securing bolts for the battery tray, 12 mm socket and remove it.
Unplug the two pin electrical connector on the side of the washer bottle, this is the washer pump, and move it out of the way. You will see the fuel filter.
You will need a 19 mm socket for the top banjo bolt and a 19 mm open end spanner to hold the top neck on the filter. Undo the top banjo bolt.
On the bottom of the fuel filter there is a 'U' pipe. On the end of this pipe there is a fixed union, 19 mm open end spanner, hold this union, do not try to turn it as it is the female. The male union is the one you undo. You will need a 14 mm spanner, preferably of
THIS type, which will prevent you from rounding the head of the union. These can be very tight at times, especially if they have never been changed.
The filter housing/bracket is attached to the bulkhead via two bolts, 12 mm socket, undo these and remove the filter and bracket together.
The filter housing is secured to the filter via a through bolt, 10 mm socket, remove this and remove the housing, noting which way it sits, there are two or three grooves in the bracket which marry up to the filter to assist correct alignment on re-fitment.
When removed you will see that the 'U' pipe is attahed to the filter by the same method as the top banjo bolt you undone first. Make a note of how the 'U' pipe sits so you don't put it on your new filter the wrong way round.
Make sure that you renew the copper washers and that you do the banjo bolt up firmly but with care not to strip the threads on the banjo bolt.
Re-fit the bracket and refit the filter to the car using a reverse sequence of the removal.
It is wise to clean the contacts on the washer pump connectors and spray them with an electrical conductive lube, we use
THIS but something like
THIS which is readily available from your local Motor Factors and is cheap enough will suffice.
Re-build everything. Re-connect the battery, negative terminal last.
Replace the 20 amp fuse and start the car. It will require a couple of moments to prime the new filter and system. Check for leaks, this is very important but will be obvious as it will drip or rather leak profusely if there is a leak.
Last thing to do is check that the windscreen washers still work as the connections on the pump don't like being disturbed, hence the use of the contact lube.
As for the gearbox, it should be a six speed box. Check the oil level and check for signs of leaks etc.
Depending on mileage it may be one of several things. Without driving it, it's hard to tell but i would consider an oil change as the first stop. Only use a GL4 based oil of 75/90, a GL4/5 is o.k. but do not use a plain GL5. Castrol Syntrac is a good oil but to be honest, these boxes run better on a less expensive oil like Comma.
I doubt very much if it is anything external or hydraulic, these are not faults which relate to your problem. The only other possibility is that the synchros are begining to wear due to mis-use or lack of g/box service.
If the clutch pedal is heavy/hard it's a good bet that your clutch is worn. Contrary to perception, the clutches on these cars are very light to use when they are in good condition and that includes uprated versions.
It may be worth your while to check the transfer box oil level at the same time, as these were subject to a recall for leaks from the seals, there is still a warranty recall on the transfer box if your car has not had it done.
Hope this helps. Don't hesitate to ask if you need further help.