Apparently some folks don't always read the photo captions, to wit:
"I like your conversions, esp. the realistic length of the loading tools."
"the tools so aptly scratchbuilt by CH"
Musketier - as the esteemed Cardinal states in his first caption, these "tools" are Foundry stock items in metal. Several other companies sell them as well, Minden being one that has an excellent set of artillerist's tools available.
Jack - Actually, separate styrene plastic wheels have long been available, although not cheap, through model railroading suppliers. Walthers here in the US stocks a set that is 1.5" in diameter and have carried other sizes in the past. You can see them here, at $5.50 for a pair. Similar wheels are also available in metal from many suppliers of wargames figures. If a proper set of limber wheels is done by WF for a single-horse limber, said wheels would be very small for any kind of in-scale wagon. A cart maybe, but not a full size wagon.
As my now long-ago thread posited, it is possible to do a proper artillery set, with crew, limber, 1 draft horse, 1 medium gun, tools and even some spare legs; but (IMHO) not on a single sprue. To do this set properly should require a minimum of two sprues, and possibly three, which is a significant tooling investment. As a result, I suspect that you will see some sort of compromise produced, possibly with some of the similar compromises seen in the Cavalry set.
BTW, as I have had some e-mails and PM's regarding my earlier ideas, and have actively lobbied for the Artillery and "spares sprue" in the past, let it be known to all that I personally no longer have any involvement in the design, feedback process or QC on any set produced by Wargames Factory along these, or any other, lines. After discussion behind the scenes with Management at WF, another route was decided upon and I have withdrawn from any involvement in the Company's products. To the extent that I have already liquidated all of my WF plastics and have moved in other directions. I wish them all the best, and I am delighted to see modelers like the Cardinal and RobH use the tools of the trade from the 70's (that many of us cut our modelling teeth on), to build some very good conversions and prove that the medium is viable for quality modelling.