in my opinion applying and taking Level 2 with out a FA cert or in the process of applying for it is odd

not against the rules, but odd in my opinion, as this means you must have gained all your stalking experience borrowing an estate rifle everytime !
Agreed, doubtless it does seem odd, from your perspective.
But for some amateur recreational stalkers who have to pay for their outings, in single figures per year, and are always accompanied by their guide, there is little incentive to own their own deer rifle.
If they stalk far from their home, there are also issues of security etc. which inhibit bringing their own rifle.
Both concerns apply to me, and using estate rifles has been no hardship, quite the opposite, and has given me the chance to use several different makes and calibres, where I otherwise would not have had the opportunity.
Perhaps I have been fortunate, but IME the estate rifles have been in superb condition and precisely zeroed. As a club target shooter I have the opportunity to use many different rifles, and have no difficulty in adapting to a new one.
None of my target rifles are suitable for stalking, except maybe my Marlin 336 in 30-30, which would be an esoteric choice for a first deer rifle. The LE No 4 Mk 2 would also be eccentric (though I have been encouraged to apply, by one of my guides, who thought it would be fun)
Buying a dedicated deer rifle will cost me the best part of £1000, which I would rather put towards paid outings, maybe even DSC2 registration and witnessing, when I am ready.
Kind regards Malcolm,
Jonathan