Series 3 petrol 2.25 head gasket

All, so the head gasket is gone. Mayonnaise in the rocker cover and the water level is dropping. I will do a compression test as a recheck but if there is anything else I should do, please say.
Questions:
Do I try and lift the head and slide a new gasket in, or strip it all off and do it properly?
Composite or copper gasket?
The head is original and not hardened but hasn’t ever missed a beat and has had additive in (owned since the days of 4*). Do I take the opportunity to send it to Turners for hardened valve seats etc I could do without spending the money and it only does 2-3,000 miles a year. Currently 90,000 on the clock.
Lastly, I know there are issues with the studs for the manifolds. Any suggestions for stud removal? I don’t have a heat option.

Any obvious pitfalls, do say. I have been spraying the head bolts with penetrating oil when passing. Hope it helps.

All suggestions gratefully received.

Head off, I remove as much as I can, makes lifting the thing easier. New gaskets all round. Composite gasket.
Up to you on turners heads, I fitted the head from a 2.5 on mine.

Assume exhaust studs are poor, if inexpensive, get anyway.

There is no sliding any thing in. Head off, clean the surfaces of block and head, composite gasket. Follow correct torque down method. Head can be remove with manifolds on but more weight. Plumbers blow lamp is a good small heat source. Some good videos on the you tube

Thanks all. Time to go into buying mode again. The basis are fine (full head gasket set + the bits known like the exhaust studds) are there any parts you might not think to buy when doing a head gasket swap? There is nothing more irritating than getting half way through a job than having to stop and wait for a minor part.

I done mine last year as the valve stems were goosed. Ended up putting on a composite gasket and replacing some bushes on the cam shaft but all in all was a great experience.

Even done a de-coke at the same time which all the pistons needed.

Have fun

Just so you know there are some core plugs in the head under the rocker shaft that can leak. Handly I found this out after I changed the head gasket!

Pretty sure I left the manifold on the head, be aware it's rather heavy to lift off.

Turners do quality head gasket sets def replace valve stem seals, I would also strip the valves and springs, rockers check for any damage and lap them in, inspect head for damage/ cracks etc and order parts once