As the Daily Telegraph pointed out, an independent Scottish Defence Force can only inherit equipment currently in use by the MOD.
So, for example, an independent Scotland might decide it only needs a relatively cheap, lightweight air defence fighter, such as Gripen or F-16. However, all they can inherit is Typhoons, which may be more expensive and complicated to operate (I'm not belittling the capabilities of any future ScAF staff here!) than they require. Similarly a Type 23 Frigate may be more than they need, but it's the only game in town for now.