Variants causing problems?

-- url of the page with the problem -- : njp-pastel-art.uk/index.php/shop/product...dition-prints-medium
-- HikaShop version -- : 2.3.4
-- Joomla version -- : 3.3.5
-- PHP version -- : 5.5.9
-- Browser(s) name and version -- : Chrome 38.0.2125.111 m
-- Error-message(debug-mod must be tuned on) -- : No error message

I read a lot on the forums before posting and have tired several suggestions but think that my use of variants is the root of problems not only in the intermittent non-show of any variant products but also in my cart/checkout which also seems to work intermittently.

Everything was working fine, even the variants, after I set it up (second time around as I had this problem with variants previously as well) yesterday. The checkout was having problems (different issue) but the variants were working fine. I deleted all the old products and set up new category names for my second attempt. I think some of the deleted products are still in the database but I am not savvy enough to know how to a) get to the database and b) how to delete them!

While sorting out the checkout (still not working) I seem to have upset the variant products so when you try to view any on the live site, you get a blank page. I checked that my index.php file has the "messages" line in it but I still get a blank page with no explanation of the problem.

What can I do to make my variants work without all this hassle or am I better off jt setting up every product individually as at least I don't get this problem on any of my individual products?

The checkout problem may or may not be related to the variants so I mentioned it here. I'll post separately the checkout forum if it's not a related problem.

Any help welcome!

Hmmm, I deleted all the variants that were currently unpublished and it seems to work again...

Oh and now the medium and small prints aren't working but large is...