>> > Or a mini master 3 pbx (at least they were small)
>>
>> No, that wouldn't helpthe OP at all.
>> The BT Minimaster III had LD extentions, and dialed out
>> to the trunks with LD.
>
> As I found out after buying one..! The London 16 is a good bet, they're
> cheap and reasonably easy to obtain on eBay, also they will work with any
> combination of LD or MF phones. The exchange line cards can be set to dial
> out on either, too.
>
> Ivor

Yes, spent many an hour in hotel broom cupboards with Londons.
IIRC they were often provided with ground-start trunks (PITA)

--
Graham.

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