Ok, so here are the first measurements of the individual drivers without a crossover.
The measurements were taken with the lash-up cabinets positioned where the finished speakers will live in my listening room.
The measurements were taken using the function within the Hypex DLCP (DSP) and with my microphone calibration file installed.
The Cyan traces are limiting filters I uploaded to the DLCP, which are just outside each drivers range. These offer some protection to the drivers when doing full frequency sweeps. The Red traces are the measured results for each driver, which includes the effect of the limiting filters. The Orange traces are the softwares prediction of what will happen if these filters are applied a second time to the measured result, so should be ignored. With this software, if you add further filters, the Orange trace will change accordingly to show the predicted effect of the additional filter/s. This wysiwyg approach is very handy for people with only a basic grasp of the technical side of things, we're not all acoustic engineers.

I've measured each driver at three distances, 12, 35 and 100cm. Volume level for the sweep signal was kept the same for all measurements taken.
What can be seen on these plots of the Left speakers HDS Tweeter, is that the rising response of the stock driver has been flattened by the wave guide. Strangely there is a 3dB roll off from 10kHz to 15kHz, I will have to compare this with the other driver, to establish if this one is faulty.

The plots of the Yamaha Mid Range show its response is falling away in the upper frequencies and by a fair amount by the time its stock 6KHz crossover point is reached, some work may be needed to help relieve this situation,

With the ScanSpeak Woofer, it measures remarkably flat at 12cm but the peaks and troughs get larger the further the mic gets away from the driver. There is no gating here and reflections/room effects show up the most with woofers.

These plots are of the drivers in the right speaker, to check for uniformity and were taken at the middle distance of 35cm.
The right Tweeter shows a similar trace to the left one, so its not a faulty driver causing the upper roll off. My Mic is calibrated to 25kHz so that is not contributing in any way. This 3dB roll off at the top can be desirable, in a non fatiguing way, so I will hold off addressing this for now.
The right Mid Range is also a good match with the left hand unit.
The right woofer is generally a good match with the left, but exhibits a 4dB increase in magnitude at 35Hz. This is probably room reinforcement as the right cabinet is located in the corner of the room.
This may explain the very pronounced (And nice) deeper bass I have experienced with these drivers/cabinets in my other projects. I will look at reducing this spike though.

I decided to take a closer look at the right Woofer. It starts out pretty flat but the 35Hz spike gets more pronounced as the microphone is pulled out into the room.

The Woofer trace is pretty flat when measured at 12cm, but I was curious what it would look like when measured even closer. This trace at 8cm on axis is impressive and is almost flat from 35Hz to 500Hz, it shows how much the room messes things up, even when measured just a meter away. It's not driver  correction that's needed here, just room correction.

The next task is to measure the individual drivers with the basic crossover filters installed.
Looking at the driver responses, this would appear to be 500/4000Hz so this will be my starting point.