270 won’t carry much weight mate. It’s also the 99bhp which is underpowered for window cleaners with big water tanks.
If you go for a custom, you want at least the 300, 310 or 320. (That’s the weight) you can also get away with the 290 quite easily. But 270 is very low on the payload.
You also really want to try and go for the limited spec. It’s got all the extras you could want, really is worth the extra money!
I’ll be selling my custom soon, it’s a 290 limited, but has done 110k. Full service history, never missed a beat. I’m upgrading to the facelift version and a 320 as need the extra payload really.