Well, I have just bought my bike !
I looked at some second hand, but mostly new.
As I am fairly small I felt that the womens specific bikes were best for me. I managed to find a few in my size, the Merida Juliet, the Trek Lexa, the Giant Avail, and the Specialised Dolce, all at different shops, but I visited each one more than once before I made my final choice. I discovered that the geometries of the different bikes were quite different, and was surprised that the 47cm trek was the correct size for me, but in a specialised it was a size 51cm that was best.
It took me a while to get used to the cycling position, as I haven't ridden a road bike for 20 years.
After viewing a few second hand I realised that I wanted to buy new.
I was worried that I would have problems reaching the brakes and changing gears, my hands do ache quite a lot when carrying bags or painting etc, but thats just my age I think - approaching 50.
The Giant was the wrong shape for me, as I was too stretched out on it. The Trek was nice, fitted me well, but I didn't like the handlebars as the drop seemed to end half way round the curve. I liked the merida, but I decided I liked the fit of the Specialised best. I have a local specialised concept store, but they didn't have the basic Dolce, so I was sized up on one of the higher spec Dolces. They ordered the basic Dolce in for me with no obligation to buy, the asssitant said " you will like it, it is such a nice looking bike", and I thought well it looks OK in the catalogue, but nothing special, and I'm not bothered what the frame colour is anyway, it's irrelevent.
When I saw it in the flesh I must say it was very smart, it looked fabulous, although it was the cheapest, it was the best looking bike in the shop !
They fitted it with some shimmies to make the brake reach easier for me, and I bought some mudguards also.
The weather was pretty awful, wet april showers so I was a bit nervous about riding it the 7 miles home, particularly as I wasn't used to using these new combination brake/gear levers. The sales assitant looked a bit more nervous than me, he lent me a high vis vest for my ride home. I got on it and tackled the ring road out of town with no difficulty at all. My younger years of cycling helped me and I was very confident, It didn't take me long to get used to the brakes and gears, and despite the bad weather I thoroughly enjoyed the ride home.
I'm planning a 15 mile circuit for tomorow, I will see how I get along and increase my distance gradually over the next few weeks.
Thankyou for everyones advice, you all helped me to figure out what was the right choice for me, so thanks for taking the time to reply to my posting.