Elddis have used both types and even at the same time on different models.The only way to be 100% sure and lay underneath and look on the chassis and axle.There is usually a small plate on the axle with manufacturer and max load of axle.Also on chassis look for name .
Easy way look at hitch head, ie part that hitches to towball. Alko hitch is retained by 2 horizontal bolts. Bpw has 1 bolt horizontal & the other vertical.
If you want to fit an Alko stabiliser hitch then some have got a vertical fixing hole at rear to allow fitment to Bpw chassis but you may need spacers for draw tube & when hitch is installed ensure it does not hit handbrake lever on full compression. The stabiliser hitch usually fitted to Bpw chassis is Winterhof but unlike Alko they are rarely found secondhand on ebay.
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