Save yourself time, money and frustration, PN. Access your unit's by-service copy of the relevant volume of Jane's Fighting Drunks or nip down your local library if you're a civvie and you'll find the envelopes of most weapons' systems and platforms in public purview and as-near-as-damnit accurate.
It's the kind of information the Secret Sams love to protect, hostile countries already know, and terrorists don't really care about. But it keeps paranoid senior officers and Whitehall mandarins in employment.
The MoD has the ultimate get-out clause. It does not have to and will not be forced to disclose anything judged not to be in the national interest. Game of catch-all anyone? The rest, as they say, is unadulterated bullshi*.