Fitting Alternator in Vauxhall Nova 1.5TD?

I have recently bought an alternator for my 1993 Vauxhall Nova 1.5TD (Isuzu lump). Having had a look it seems this may be very tricky to replace (certainly no access from the top). Is this something I can attempt myself at the side of the road or is it something that would have to be done by a garage due to its position and having the vacumn pump on the back of the original.