I can't help with the signage, but why not generate your own equivalent by writing a simple route card?
Here's one that I did for one of my forum rides:
ColinJ Glasson Dock forum ride 29/3/2014 route
SO = straight on
TL = traffic lights
O = roundabout
T = T-junction
LHS = lefthand side
RHS = righthand side
L = left
R = right
BL = bear left
BR = bear right
sp = signposted
WHALLEY to GLASSON DOCK
Start SPRING WOOD picnic centre car park, A671, above Whalley
SO TL, descend hill
R at mini-O in WHALLEY at 0.8 km
[Cafes on LHS after ped crossing & before bus stop.]
L on B6246 at mini-O at 1.1 km
R at T at 5.4 km (sp Trough of Bowland)
SO (BL) at 6.5 km (sp Trough of Bowland)
SO at X at 7.9 km (sp Trough of Bowland)
SO at 9.4 km (sp Trough of Bowland)
SO at BASHALL EAVES at 10.2 km
Continue gradual climb to COW ARK at 13.6 km
BL and descend to Lees
R at T at 15.4 km (sp Trough of Bowland)
Stay on that road through WHITEWELL to Dunsop Bridge
SO at DUNSOP BRIDGE at 22.3 km (sp Trough of Bowland)
[Ride through glorious TROUGH OF BOWLAND]
Assemble at summit of climb at 27.2 km for group photo
L sp Scorton at 31.5 km
SO at 33.8 km
BL at 38.2 km
R at 38.7 km sp Bay Horse/Galgate
SO at X at 39.5 km sp Bay Horse/Galgate
SO at X at 40.6 km
SO at X at 41.1 km
SO at X at 42.4 km
SO at 43 km sp Galgate/Lancaster
BL under M6 at 44 km
Cross A6 SO at TL at 44.7 km in GALGATE
**CAUTION** s-bend under viaduct at 44.9 km!
BL at T at 45 km
Stay on that road until L on A588 at 48 km
Almost Immediate R sp Glasson Dock
SO at mini-O at 49.2 km
L at 49.7 km in GLASSON DOCK
Cafe stop at Lantern O'er Lune on RHS at 49.8 km
You could navigate that 50 km route by just following those instructions and using a cheap bike computer to check the distances. (You can use Google Street view to check the available road signage before writing the sheet.)