I had chronic SPD and was on crutches from around 22 weeks too.
I was panic stricken about labour, but Iwasn't offered c section, I was however induced at 37 weeks.
Labour wasn't easy as I couldn't get mobile and towards the end I was shouting for epi, mainly 'cos cobtractions back to back and constant pelvic pain and mw said only 5 cm dilated, so decided couldn't take anymore.
Never got epi as LO arrived as they were trying to set it up.
My SPD didn't wear off as quick as Amandas, I was on crutches for 6-8 weeks after the birth, gradually needing them less and less.
I wouldn't say it has gone completely sometimes I have problems with discomfort, past week or so can't lay on RHS for long.
Does make me concerned about ttc again ( poss next year) as I don't particularly want to go through it again, some ppl get it worse with successive pg, but then some ppl I've spoken to didn't get it next time round.
I can imagine work being impossible for you Tabs on crutches, I'm, an optom in store & not mobie/domi, and I really struggled, until I went on maternity.
I have every sympathy for you girls I would only wish this on my worst enemy.
Make sure you get as much rest as possible, and take it as easy as you can.
Wishing you a short easy labour ( you deserve it).
Often pop on to see how everyone doing, but not posting much due to work, but if anyone wants to chat/ ask q's pm me and I'll add you to msn as always around for a chat.
Big

to you all
Carolinexx