I tried to post this at Fpace section but no luck, maybe someone could help me from XJ section:
I was thinking to perform fuel treatment services for my Jag and I was wondering is there a fuel return line?
Looks like there are 2 separate lines going in to the engine. Are both or them are feed lines?

 

The AJ133 fuel system is returnless, i.e. no fuel return line.
I'm fairly sure the two lines you have circled are the low pressure and high pressure lines, dunno which is which though.
For a fuel treatment service all you need do is whack a bottle of your preferred secret sauce in the fuel tank, I use BG 44K and Redline SI-1, another popular brand around here is Techron.

 

BG 44k and Redline is great but i prefer BG. I have some more potent BG stuff laying around, it cleans injectors much better on top of that it removes carbon from combustion chamber.
Also will be will be doing intake/induction/valve cleaning service.
If it is "return-less" fuel system it should be only one connector, high pressure fuel lines are always metal ones.