Ho ho. Tremendous. I won a stuffed turd kind of toy in the summer with a 275! My daughter has strange ideas. Seriously, these are great fun guns. They are obviously extremely robust and I've found the Anschutz very accurate for a ball firer. The Haenel 310 is the ball firer and I have not used one. I do have the 311 with the same action and it is excellent. The H & N 4.4mm copper coated balls work well in the Anschutz.
I've seen a few 275s around the 200-250 quid mark recently. Have not seen a Haenel 310 for sale.
There is also the Diana / Original model 30 to consider. Have never seen one in the flesh but they look more substantial looking gun than either of the above. Rare, though.