That price probably excludes the excess for the exchange part, so your maths might be round the wrong way LZ
I agree, the alternator fault is more likely to be the regulator pack on the back, which is the cheaper fix.
Alternator is a bit fiddly on the Omega, but not difficult. Like many jobs, access can feel tight. Be defo do-able.
But the first thing you must do *RIGHT NOW* is get that battery off and on charge. Leave it a day or 2 and I promise the battery will be shagged.
Well all I can say is that the AA guy, who was a Vx mechanic working on the Carltons, Senators, and Omegas did his diagnostic check and concluded the alternator had expired. Not surprising really on a 20 year car with the original in place. I had one expire on a 6 month old Ford Cortina estate back in the day, and what I experienced then was the same this time.
Frankly, for the price all in, and yes I have had confirmation that I get my £47 back with the old unit, which comes at a nett price inc. VAT of £87, I cannot deal with all the hassle of mucking around now. nA Vx dealer who I know and trust is assisting me with all the arrangements, and the AA are on standby to take it to them on the day using one of their own batteries that will cover the short distance. Before they left me the other day, they used a charger to start the car and recharge the battery just a little for all the electrics to work. I understand though that the 2.5 year old battery could now be u/s, but I'll cross that bridge on the day.
Thanks for all the advice though, but it is just a shame that I, now 70 years young, cannot deal with all the hassle of doing it all myself on a part that is fiddly to get to. Also, for the set price quoted professionals can check everything out. I may well get them to test the regulator pack before fitting the new alternator. They can aLso check the battery as suggested.