I have two RN27 axles and they both measure 1370mm drum face to face, so I would be telling you, that you do not have an RN25 axle.....sorry about that.
More likely an RN30/40 axle.
Return it for a full refund and start your search again.
You can roll the guard lips and play with wheel offsets to get you back under the guards but it will be a pain in the arse.
Its likely that you will not get your prefered wheels and tyres under the guards and have to run standard size rims and rubber that you will hate.
Much easier to get what you paid for in the first place.