RaspBerry Canes

Raspberries, once established (give it at least 2-3 years), readily spread out and are easy to split the root/canes in autumn for more plants.  When first planted, some canes in the first year may take a little while to start fruiting well but thereafter you should get good harvests.  18 sounds a lot (but then I got a total of 22, different varieties for early, mid and late cropping so who am I to judge LOL)

I've bought canes from various online suppliers like DT Brown, T&M and Mr Fothergills - to be fair, most are fine but I may have got a bad batch from one of them as one lot of new autumn planted canes have withered and died one after the other (I'm not sure why - I've never grown raspberries or strawberries in that particular bed, but it looks a lot like raspberry blight ...)  If I was honest, the best ones I bought were from the garden centre already planted in pots @ £5 per pot.  Although they had started growing (Easter), I carefully split the bunch into 5 individual plants and they are already way ahead of the bare rooted canes I had bought last year.

I'd probably wait until autumn before re-positioning established canes into a new bed.

As for your row - 18 canes in an 18 x 1 ft row seems a bit tight.  Raspberries spread by sending out underground shoots (new canes) away from the main plant - your neat row will have new canes coming up where you might not want them away from the central row as well as towards each other.  And some raspberry varieties fruit on the new canes rather than old ones so removing them is not a good idea.  I think I'd be a bit more generous with the spacing to be on the safe side.