Replace Fuse in Fiat Ducato

[Brian49]

We have a Motorhome
There is a starter battery in the Fiat Ducato (prime mover)
There are 2 deep cycle House Batteries.
The Starter battery is connected to the House batteries via a VSR (Voltage sensitive Relay) which enables the alternator to charge the house batteries when the starter battery is fully charged.
Recently the Starter battery died and to get it going we had to jump start it resulting in blowing the 150 amp battery mounted fuse. If I want to replace this fuse like for like I need to replace it with a MRBF (Marine Rated Battery Fuse) Photo link below

(Had to exclude the link due to restrictions in the forum)



There is limited room within the well where the battery is installed (under the passenger floor) however a fuse similar to the below link (plus a fuse case) would fit more easily than the original MRBR

(Had to exclude the link due to restrictions in the forum

My questions:

1) Why would the installer (unknown) use a MRBF (its waterproof) in a motorhome and is it necessary to replace it like for like?
2) Would the alternative mentioned above be an appropriate replacement? (After all its still a 150 amp fuse.)

My thoughts are that I could use the alternative as a replacement but I am not an expert.

Hopefully there is an expert out there who can give me some advice.

Many thanks

 

[Brian49]

These are the images referred to in my previous post.
the second image is only the case of course