Starting out with your current knives, I've done a quick look-up - and the Sagaform Edge knives definitely are not the height of Western Civilization in cutlery. With 4116 steel and a hardness of 53 to 55 Rockwell C hardness, that's a description of mediocrity. An 8 inch blade is also nothing to look to as a significant standard. Virtually ANY of the knives discussed will be a big improvement. For that matter, the 53 pound IKEA damascus Slitbar with a VG-10 core would also be an improvement, though it's nowhere as good as the aforementioned knives (just be sure it's the damascus Slitbar - there's another Slitbar Chef's Knife which is a lower grade).
Since you have larger hands, there should not be a problem with either a western handle or a Japanese handle (there was a significant discussion this month about someone who had small hands and major problems with the available knives).
Many of the cooks and chefs here use the pinch grip and believe it helps in the control of the knife. It also makes it much less relevant as to whether you are using a western or Japanese handle.
By "a la carte", I am presuming you mean whatever a customer orders. I will interpret that as general western-style cooking, including "meat and potatoes".
The one real change here is to strongly suggest you learn how to sharpen using water stones. More than anything else, that will make a significant difference. In fact, if I were looking at your budget and deciding between spending 200 pounds and getting one quality chef's knife, or paying 53 pounds plus VAT for the IKEA Slitbar, and spending the rest on good quality water stones (at least 20 cm long and 5 cm wide), I would do the latter. All knives get progressively duller with use. That's true of expensive and inexpensive knives alike. Buying an expensive knife will sooner or later be just another disappointment if you can't keep it sharp.
With a VG-10 steel core knife, you will need to use a progression of 3 stones, 1K for restoration of an edge, 3K to 5K for reducing the bead and for edge polishing and final bead abrasion.
While it is from an American internet retailer, you might consider the following kit from Chef Knives To Go, which has the Beston 500, the Bester 1200 and the Suehiro Rika 5000 stones, along with a 20X loupe magnifier and a felt deburring stone, which is offered for $139.95 (about 86 pounds). http://www.chefknivestogo.com/3pcstoneset.html You will also need a stone flattener, to remove the inevitable dishing. A good one is an inexpensive diamond plate, also available from CKTG for $29.95 (slightly over 18 pounds) http://www.chefknivestogo.com/140grdistflp.html Shipping and import duties will of course be extra.
You should also read the following post by Chad Ward http://www.its.caltech.edu/~gbelford/KnifeMaintenance&Sharpening-Chad_Ward.html
It's a distillation of his 2006 book, An Edge In The Kitchen, which is worthwhile to read by itself, though the price information is hopelessly out of date. I've generally recommended that American participants to this forum go to their local public library and read it there, or through an interlibrary loan program, but I don't know what the procedures are like in the UK.
You can also watch videos about sharpening. Jon Broida of Japanese Knife Imports does excellent on-line videos and you can also watch Bob Kramer and Murray Carter. CKTG also offers a number of informational videos on sharpening.
Hope that helps
Edited by Galley Swiller - 9/13/14 at 6:56pm