lets just confirm tank size 1st as you did ask at the start but it got over looked
for a adult pair of Leos you would need a 8 x 4 ft tank
a pair of Leos cheapest price in the UK would be around the £800 mark you may get them cheaper from Holland or Germany and its not that bad a drive just jump on the euro tunnel at 6 am drive over to Holland get there around lunch time drive back home then the rays will be in your tank by 8 pm
if you want something bad enough that drive is nothing and its better than getting ripped off
for normal motoro you are still going to need a 8 x 4 ft tank and you may get away with a 7 x 3 ft tank for a real nice pair or marble motoro
if that tank size is to big for you go for a pair of hystrix as there are some cheap ones going about at the moment and you should be OK with a tank size of 72 x 30 inch