Have a read of the newbies section,my advice would be to go second hand Planet Eclipse.
Sell the Delta Elite for £150 ish expect to pay £250-300 for something nice.
Go platinum member to allow you easy access to sales section.
Ask people's advice before you buy.
Planet eclipse markers are very good, I brought an ego 10 as my first marker and it's never let me down .
I'm looking at getting a second marker and was told to stick to planet eclipse markers as they are reliable.
I used my Invert Mini for the first time on Sunday, such a boss marker, the firing rate is ridiculous, so accurate, so damn light, reliable, and easy to work on if need be, a very simple thing.
2nd hand can easily be had for £150, I paid £180 but was the limited edition and pretty immaculate.
TM7 would be a better choice, goes full auto and works really well ( oh no I mentioned full auto but I won't start that argument for a few months when I decide to attack UK paintball over claiming Paintball guns are firearms ( which they are not ) after one discussion with a retired fire arms officer ) but look into that it's awesome, or a X7 Phenom, I used to use rock that until it pissed air.