There was another kit available a few years ago. I think it was made by the Borg Collective and available through Federation Models. It was a recast or repop of the Lunar kit, if I'm not mistaken. There may also be detail differences. It's been years since I looked at the kits.
I have both, but I may have to throw my arms in the air and finally admit that I'll never get round to finishing them off.
I did make a start on the Lunar kit, but my inexperience with vacuform methods and the strengthening that the kit would have needed eventually forced me to put it to one side.
The droop in that picture can be explained by the upper hull decks being a sold resin casting that weighs about 2-1/2 lbs, if memory serves.
I might be persuaded to part with one or both. Only trouble is I'm 8,000 miles from Hampshire!! (Hong Kong to be precise.)
The Lunar kit will prove a little troublesome digging up as over the years I have not kept the parts in one box, but the Borg version is all boxed up, I'm sure.
Cheers
Steve
PS; If this question had been asked three months ago we could have had it all sorted as I was back in the UK in June!