Been a while since I had a Series 2 on the go. However the thing that caught my eye in your pic is the nut on the master rod. Two my eye it just looks bigger/thicker than an original one. A narrower one would allow the tad more free play you need...

No idea about LOF, have not used them. I have replaced mine with the standard servo/master. Noticeable improvement over the old.

Flush new fluid into your system as brake fluid is prone too deteriorate over time which could be the soft pedal condition you mentioned, & as above regards the brakes

Check that the little wire from ignition switch to the starter solenoid is not live all the time due to ignition switch or wire fault.

No too thick won't add resistance, just harder to bend and more expensive

I did find it terrible before I actually had a look at anything. I then found I had no thermostat fitted, replaced with a 78 degree one. I then found all the foam seals in the heater box had disintegrated, same with the dash air box, after...

I used Tigerseal

Original is some sort of nylon washer. A ring cut from a suitable size alkathene pipe warmed in hot water to soften enough to slip on could do the job and last some time.

It is my opinion that in recent years Britpart have upped their game, doing more testing on the parts that suppliers send and rejecting the poor stuff. There is also the issue of " Fake" stuff. Had some Brake cylinders from on line site that...

With regards to Paddocks make sure you find out the supplier/manufacturer first ..........if they will tell you. AFTERMARKET means anything could turn up. Actually they have worse than Britpart, believe it or not.

Your replacement is likely a series 2/early 2a one. If the bonnet has hinges held by 4 bolts this confirms. later bonnets have 3 hinge bolts.