You have an electrical short in that circuit. The fuse is doing its job, preventing a fire (barely). You need to find where the short is before trying to operate this vehicle again, or you will end up setting it on fire. Look for the burned/melted wires.
Its never to late to panic, but before you dive in check the battery.
If during the crank the voltage dips very low the state of the ECM can become erratic and trigger a limp home mode and throw codes..
Resetting the ECM (Engine Control Module) will likely fix the problem..
Check the battery make sure it is full charged and reset the ECM by disconnecting the battery or with a scan tool.
If the battery is defective it will happen again.
If the battery was partially discharged before the problem it may not occur again.
If it's the petrol k series 1.8L or kv6 2.5L engine then the starter motor is only held in with 2 bolts and can be done from above, so no need to remove wheel and arch liner. See me doing in on a mgzs here, the freelander has the same engine so is similar:
https://youtu.be/rtuMCh3iIlw
Get a torch and look all round the engine until you see the source of the leak.
There are only a couple of options namely:
1 Through the engine, meaning a blown head gasket so you may not see where the break in the gasket occurs
2. A leak on the outside of the gasket - you should see this
3. a cracked head requiring specialist work
Check your distributor, particularly the cap and the wire that goes into the center of the distributor cap. Could be a loose/bad wire or a bad distributor.
My wild guess, Fuel injector that was dirty, is now clean and is not working quite right. Have you had the error codes read? Your favorite auto parts store may read them for you.
Hi always use fully sinfetic,if not shore just give land rover a call and they will tell you the best oil for this motor.
(sorry about the spelling,all the best.