Some land, maybe, but not a lot - compare the space into which the elephants have been put with the size of the dinosaur section here:
Google Maps
But who owns that land? If not the zoo then using any of that land is subject to agreement with the owner. It's not inherently free for the zoo to use. There is a little space between the lions and the zoo boundary but going any further than that will need them to buy/lease land from the hotel. There's an ambiguous space between the tigers and hotel car park that looks to me like it has a public footpath running through - is that what you mean? If so, even if they can negotiate to use the land they will need to preserve the right of way.
I don't think you can count Blackpool as having massive room to expand. It's certainly not got space 'available' the way it is to Chester, Yorkshire and Wild Place (and indeed Whipsnade), who all own large amounts of undeveloped land themselves. They can push the edges out a little at best, then they'll come up against other landowners and unless they are prepared to start buying out the golf courses they'll be at their limit.