Mrstapir - Sorry, that I don't know what the current guidelines are now as dd was 13 last autumn. When she was born in 1997 the guidelines for weaning were after 4 months. At that time she was waking at 5am for a feed due to hunger, so I was told by hv that it was definitely time to introduce solid food.
She started with a childminder 1 day a week, then 2 days, then 3 days for my last 3 months of maternity leave. During that time, she had 1 formula feed a day (at about 2pm), and her other feeds were from expressed breastmilk that I had frozen and taken to the childminder.
I went back to work when she was about 26 weeks old, and continued to give the childminder frozen breastmilk as often as I could.
By that time, she had started on various fruit and veg purées, but I continued to bf at 6am, 6-7pm and 10pm which I kept up until she was a year old, with a 1hr/40mile drive morning and evening. Gradually the 10pm feed dropped, then the 6am one, and finally the 6pm one, when she was 21 months old.
The last one only stopped when she changed nursery and got such a bad cold that she had difficulty swallowing. After she had recovered from the cold, she didn't seem to want to start again.
So, from my experience, it was possible to combine 3 feeds a day with working full-time and a longish commute.
I don't want to suggest that you go against current guidelineson weaning, just hope to reassure you that from my experience it's possible to combine a return to a full-time job with 3 feeds a day, and the rest could be made up of either formula or purees as appropriate.
I found my first morning really surreal, walking round the edge of an office builing in 'work clothes' thinking that just 2 hours before I'd been breast-feeding at home.
Good luck with your return to work.