I have just been out collecting rose-hips for the first tome - with a view to making syrup etc. and found plenty of what I would call rose-hips. However in the same area we spotted some plants that looked like Roses but were generally much larger and had large black fruits on them (which were very spikey). Can these be used as well ?
Rose hips usually are only available on non-hybridized roses. The Rosa Rugosa is the best variety from which to obtain hips, since it is the original, ancient parent of most modern roses... Here's an article and some pictures. Personally, I'd steer clear of anything else, especially something as obscure as your description...
Probably the same species as Clanad's picture, but in the UK the rose hip comes from the Dog or Briar Rose. Have a look and see if they are the same as I'm no gardener.