Welcome to EpoS Wizard!
OK, I have two Sharp UP-700 tills (both are standalone, most likely North American models) that I've been asked to fix some items with wrong prices, add a new item with direct key, and try to put an employee discount button on. I found the manuals on-line and did up the first two no problem, but this third one has me stumped. 'Group Discount' looks like the easiest way, how ever, from PGM2 I can't edit them, throws a 'Entry Error' when I pick '1 GDISC%1' and press enter. I feel that it's some stupidly small detail I'm forgetting.
And yes, we have a gently tweaked Manager key already. Would never have known that the key was modified if it was not for these forums.
I don't think the UK 700s do group discounts!
Personally, I'd just set up a discount button. There should be one anyway on your keyboard. If not, you can put one on from 'free key layout' in srv mode. Go to srv, settings, free key layout, arrow down to %1 or %2 etc, highlight it, press the key position you want it on the keyboard then finish off with the TL button.
To program it, go to pgm2, setting, 03function, 02% then set up what you want the discount button you put on to do. This bit is in the operator manual in case you get stuck.
According to this UP-700 manual (files(dot)sharpusa(dot)com/Downloads/ForBusiness/POSSolutions/PointOfSaleSystems/Manuals/pos_man_UP700.pdf PG 117 for Group Discount. PHPBB wont let me post the link normally, just remove (dot) and put a period in), they can, at least for the North American ones. The only problem with the % discount keys it that we have ~110 items, most of which have been direct keyed with some in menus, can't fit in the 100 PLUs across all five % discount keys. I'll be a little more clear on the restrictions that have been placed on me to do this, the owner wants a one-press discount-all employee discount button. She may want another discount button for another group (seniors or students) at a different rate later. I'll look into the settings in case I've over looked some kind of enabler for group discounts. The funny thing is that it throws a very generic error on entry rather than something more descriptive.
Also, the ROMs in the UP-700 are different here in North America, function is #4 on mine v.s. yours at #3, and there are settings to handle Canada's doughnut tax exemption (taxed unless it part of a group of 6, and I don't know why we do that).
By discount, are you meaning different prices for different people? If you are, it might be easier to use price levels. That way the the plu controls if it's taxed or not regardless of the price. Unless of course Canadian taxes make that impossible!
That's getting to be a little too much work to try and cram in the few minutes I have between ringing up orders. I'll give group discounts one more shot then try price levels next time I get a chance. I'll post back once I get one of the two working or need help on the later.
And don't get me started on the tax system here, last place I was at fell into a no tax bracket (I forgot how they managed that legally, as it was not yearly sales under $60k) and need to fill in large amounts paperwork each year just to put a big, fat zero at the end. They forgot once about the paperwork and the government filled in $40k for taxes owed because they figured that was about right. 
