Well, to be fair, balance it correctly... Assuming you use avios for positioning, and willing to go Y, plus usually no need for a hotel on the way back.
I'd say £1750 + 28K avios + £70 (just from a flight search, never redeemed avios for SH, could be more or less)
Plus hotel one night £60 random date
Also earn back about 30K avios, covering positioning flights.
The difference being £750 or 125K avios. Buying those avios is about £2K (I know people don't value it this way, I do, so just saying).
Earn TPs on the PSA flights.
Can also use the 2 for 1 on the positioning flight I suppose

While some people might think it a waste, if its going to not be used...