Yes, the spikes are quite nasty aren't they

But mine seemed to lose them once it got to about 3/4 inches long.
I've noticed this morning that about 6 of the others are now starting to grow, whereas they've stayed about half an inch long (ish) for weeks now.
I'm glad you said tomato food as that's what I've been feeding mine, so at least I know I'm not doing too much wrong.
I'm interested to hear you can collect seeds from the plant, will have to keep my eyes open for them as I will def be growing more next year, can't wait to eat a home-grown cucumber.....and I've just realised how pathetic that sounds, but I don't care !!