Above there are explanations of why it is preferable on grounds of redundant safety to light the rear of the bike with a steady dynamo lamp and blinking battery lamp. The Cateye TL-LD1100 was mentioned as a superior battery lamp, capable of going 200 hours on a set of batteries.
I've come across a photo of how my 1100 was fitted to the rear crossrail of the rack with tie wraps (white). The steady lamp is not visible because the bag hanging over the sides of the rack covers the mounting under the top surface of the rack and about four inches forward from the LD1100. Both are visible from the rear, and the Cateye LD1100 has two LEDs to each side too, which the tie wraps don't obscure. The sideways tie wrap is to keep the battery cap on -- if you lose it on the road, the one weakness of the lamp design, your lamp is toast because you can't power it and the two sideways LEDs on one side are actually inside the cap.
(http://www.coolmainpress.com/miscimage/andre_jute_doctor_s_bag_open_2017_800pxsq.jpg)
andre_jute_doctor_s_bag_open_2017_800pxsq
The reason for tie wraps rather than using one of the several bike-side mounts that come with the lamp, is, first, to secure the cap mechanically, and second to secure the lamp against theft -- a new set of tie wraps after 200 riding hours is neither a noticeable cost nor a great nuisance nor does it take much time -- I had it down to about a minute to change the batteries and refit the lamp.
Anyone got or got pics of a dynamo light and cats eye next to each other on the bracket ?
You have the wrong idea altogether. Except for the mudguard lamps like the Seculite, all the lamps people have been recommending to you here are a fistful. If you somehow manage to fit a Cateye 1100 beside a B&M Line Plus or any of its relatives, all you'll have succeeded in doing would be to make your lamps vulnerable to being smashed. The bike in the pic below is huge; you're looking at a 60mm tyre covered by P65 mudguard, the widest normally available for touring bicycles. You can see how wide the 1100 on the rear rail of the rack is, and that the lamp on the rack bracket (the most desirable before or two before the Line Plus, which isn't all that much narrower) is mounted in from the far back of the rack, and protected from the sides as well. The two side by side is a recipe for continuing expense, and such lamps cost substantially more than the proverbial cup of coffee. Basically, if you have two rear lamps, the only sensible mounting plan is one above the other.
(http://www.coolmainpress.com/miscimage/Andre%20in%20town%20with%20Kranich.jpg)
The second photo shows the same bike with the Cateye 1100 fitted above the B&M Line Plus on a somewhat narrower rack, but still wider than the Tubus Fly which will no doubt sooner or later be suggested to you.
(http://www.coolmainpress.com/miscimage/andre_s_kranich_fitting_cateye_tlld1100lrearlamp_on_tubus_cosmo.jpg)
The third photo shows the front of the bike with a dynamo lamp fitted to the fork crown and on the handlebar a small but powerful Chinese torch with several blinking modes and steady modes too, serving the double purpose of characteristic bicycle identifier and an emergency lamp if the hub dynamo goes down (never happened yet). This is, given accident mode likelihood which you referred to the other day, a more important lamp than the rear blinky, always given that you have a good steady rear lamp fitted.
(http://www.coolmainpress.com/miscimage/Andre%20on%20Kilbrogan%20Hill%20with%20Kranich.jpg)
And in the two links below you can see the visibility of the various lamps at maximum power (in order to get a good photo, I'm driving them with a multi-full-amp-hour battery capable of delivering more current than they can ever demand, same as the makers do for their photos of light throws) on multiple photographs:
http://coolmainpress.com/BICYCLINGbuildingpedelec5.html (http://coolmainpress.com/BICYCLINGbuildingpedelec5.html)
http://coolmainpress.com/BICYCLINGbuildingpedelec6.html (http://coolmainpress.com/BICYCLINGbuildingpedelec6.html)
And note the reflective yellow belt I use to tie down the bottom of the pannier basket.