Tom;
Symptoms sound like the amount of Clutch Fork actuation has (suddenly) decreased (and you're not completely disengaging clutch, which would explain difficult shifting)...this can be caused by a stretched Clutch Cable, (some strands break, and nominal length increases, which might occur suddenly, and result in your symptoms...this can be adjusted out if your lucky, and
might last until you get home) or the dreaded fractured Clutch Fork (where a sudden failure and symptoms are also typical...sorry to be the bearer of bad news)...perhaps it can be adjusted, but difficulty shifting typically returns and gets worse as CF fracture opens further and CF action gets less because of it...
Certainly have it looked at, but short of having a replacement cable on-hand if the former, adjustment is about the only thing which can be done (replacements may be easily available...it's worth asking...installation is relatively simple, and can be done at the side of the road in a pinch...not so much fun on holiday, I understand!)...if the later (this might be visible, see:
https://www.sw-em.com/Clutch_-_cable_actuated_Notes.htm , shift carefully, matching revs...if reverse gear is absolutely necessary, stop engine, shift into reverse, restart...better yet, don't park such that you need reverse...driving without a functioning Clutch tests a driver's metal (and vintage Volvo owner's dedication!).
Good Luck and Good Travels