What capacitor values?

If those speakers are 8ohm: the 200uF cap will cross at 100Hz and the 1.76uF over 10kHz. If they are 4ohm drivers: 200uF= 200Hz, and 1.766uF=somewhere over the rainbow, I mean- over 20kHz. I seriously doubt the mid-range actually has the ability to reproduce that range of frequencies accurately. If it does, I'll buy a truckload of 'em from you! If the tweeter is a nominal 16ohm piece, it would come in at 5kHz, but the cap on the mid might as well not be there at 16ohms. Or are those the values you were thinking about substituting? Most people use 8ohm drivers when building their own systems. It would be good to know with what you're dealing. Do you have a multimeter? Here's the formula for capacitance per your impedance and cut-off desires(for a 6db/oct slope): C1(in uF)= 1,000,000/6.283 X speaker impedance X desired x-over freq.

Thanks Rodman,
The Tweeter is 6 ohm and the Mid/Woofer is 4 ohm.
The Tweeter at the moment has a 2.2 uF cap and the Mid I believe has a 10 uF cap.
Should I stick to these values?

Well- That would bring your tweeter in a little above 10kHz, and your mid- right about 4kHz. The mid isn't doing much midding that way. I'd say 80uF on the mid(500Hz) and about 5.5uF on the tweeter(about 5kHz). I suppose if you were to go with an iron core inductor on the woofer, you wouldn't have as much insertion loss(though it may become non-linear at high input levels). If I were doing it, I would use either Solo or Alpha-Core air core inductors(very low insertion loss and phase shift, very transparent). The value of the coil would depend on the impedance of course(8ohm=2.5mH, 4ohm=1.27mH for 500Hz). I suppose a .13mH to roll off the mid at 5kHz wouldn't hurt either. You may find yourself having to pad the tweet and/or mid to match their outputs with the woofer.

Thanks again Rodman.
Whilst the formulae indicate that with the 10uF on the Mid it should only come in at 2000Hz, it patently doesn't.
The speakers have always sounded effortlessly brilliant as all my audiophile friends agree.
I don't want to mess with that distinctive balance and by inserting new Dueland VSF caps for the existing cheap 30 year old ones, I hope to hear improvements.
The Scanspeak tweeter comes on song at 1500Hz so I don't understand your thoughts on pushing it up to 5KHz?
I thought if I left the tweeter at 2.2uF and increased the Mid/Woofer to 40uF (compared to the 10uF it's had for 30 years?......it might improve the overall sound without affecting the character that I love?
What are your thoughts on that?

If you like the sound: Leave it as is! You've no one to please but yourself. Based on the impedances you gave, the values/points/slopes should be as noted. I was suggesting what generally works well for x-over points. Especially with a 12"/5 1/4"/and tweeter. Happy experimenting/listening!