Hello and welcome from Denmark. Glad you've found your way here and I'm sure you'll find lots of things of interest. If you're going to collect just one car brand, Citroën is probably the best possible of all. I don't think any other make is so well covered, right from the vintage days of Dinky, Corgi, Solido etc. up to the modern age of high tech models. Heck, both the Traction and the 2CV even have their own series!
I've taken a look at your website and you really have some great models in your collection, although it seems you've also encountered the classic problem of some cars only/mainly available as rally/racing versions. I find this really baffling - I mean, a company create a rally version of a certain car, so they basically have the mold, the have the licenses, the measurements, everything... why don't they do that little extra work and issue a street version like the one we see in our everyday life?
With Citroën, the overall coverage seems quite good, but the problem here appears to be the more recent models like the Xantia, Xsara, C2, C3, C4 and so on - it sounds crazy that you have to buy a model from China in order to get a current European car, but I'm really not surprised.
I have many Citroëns in my own collection, both old and new, some common and some not so common (like a CX from Verem, a GS from Politoys, a DS from Vitesse and a Visa from Cougar), more recent castings include both a Dyane and a GS from Ixo/Altaya - all in 1/43 scale. Because there are so many models to choose from no two collections will ever be alike... new models are constantly discovered, and I'm looking forward to discovering more of yours.