Today was a bad day:
while trying to jump-start my dear in order to investigate the leaks, for unknown reasons (......) I connected
cable red + to
battery - and
cable black - to
battery + (lol but sad), the under bonnet ceramic BATTERY 80A fuse had blown up instantly, after that, horns suddendly kicked in .... Turned off key then I tried to reconnect cables in the right order but car didn't start (horns quiet this time), I could hear fuel pump but no starter motor noise... dashboard battery light was blinking. Maybe something rather than that 80A fuse has been damaged? Is it a common fuse or am I forced to buy it from a Rover dealer? Here's some pics of it:

It was an epic fail indeed.
There is a lot of this type of failure about. Did you use a Payen gasket or a copy? Was the block face cleaned down to bright metal?
Your choice now is to -
1. Leave it for a while and see if it gets better. A couple of reports say that theirs sealed up after a couple of days running.
2. Use some K seal or similar in it. Always a bit hesitant about suggesting this, but it is one case where it might be the answer.
3. Strip and fit a new gasket.
I used a copy bought on ebay, dealer's name is gasketsforclassics.co.uk, you can see the hg
here. I hope it could seal itself, I did almost 40 KM since hg change. At first there were no leaks, then it started leaking near exhaust manifold, then it dried/crystallized and stopped. Next day started again.
The face block was cleaned down to bright metal

. I'll try choice 1 then if it fails choice 2.
* Do you think re-tightening headbolts in sequence a 90° more would help?
Or
* What about tightening only bolt 10? Maybe 25° at a time.
The only thing that springs to my mind
What were the liner hights like ? if one was low then is it possible that the affected cylinder is pressurising the water system?
another suggestion could the block be warped? never come across a warped one but a first time for everything.
Just another thought, could you have damaged the gasket when refitting the head ie did you rest the head on the gasket then slide/wiggle the head arround while trying to locate it on the dowles.
All a little off beat ideas i know but something must be causing the leak.
I measured liner heights with a feeler gauge and it seemed to be within tolerance.
Cylinder block looked weird nearby its thin edges (exhaust and inlet sides), I think the right term to describe it is "porosity", it had little craters in it, but not in proximity of the exhaust manifold corner where is leaking currently, to be honest alloy nearby the exhaust leak (see markus pic above) looked bright and clean, without signs of corrosion/porosity. Maybe the block could be warped, I should have measured it with a steel ruler before doing the job. Cylinder head had lil craters too, fire rings were ok, head was skimmed then reassembled by a official Rover mechanic chief. Craters on cylinder block (exhaust/inlet thin edges) were completely crusted by crystallized cooalnt, had to remove this crystallization in order to have a flat bright surface.
I did take extreme care handling the gasket (and head saver shim) and there was no problem to fit it into dowels (no slide/wiggle). Appearance of the gasket seemed fine, no signs of distortion, cracks, etc.
I've taken few pics of thermostat and inlet manifold, click thumbnails below to enlarge images:


















In addition, my car always suffered from weird electrical problem that makes rad and A/C fans start totally randomly, could this be related with overheating?
Yellow rad fan can only work at low speed, while black A/C fan runs at high speed.
Your answers are very appreciated, thank you guys. Have a nice weekend.