But, with trading and share points tight, his decision to go it alone has surprised many.
Lench is one of the grand old men of TV sales. Enormously popular among his peers - he is generally known as "Mike Lunch" - Lench became a millionaire following the Granada takeover of LWT in the early 90s.
Peers recount fond stories, such as the recent occasion when Lench visited his GP. When asked how many units of alcohol he drank a week and told that the maximum recommended limit was 28, Lench is reputed to have replied: "Dear boy, I spill more than that."
As for clients, so far he has only signed up S4C, a Welsh-language channel that can best be described as being on the fringes of media.
There are rumours that Lench is also in negotiations with the Hallmark Channel and Discovery Kids to represent their airtime sales. While being nice properties in themselves, these are hardly going to get the average TV buyer foaming at the mouth with excitement.
The obvious question, therefore, is why is he bothering?
While there is undoubtedly a market out there for those TV stations that, for whatever reason, are not happy with their current airtime sales arrangements, the key reason seems to be Lench's relationship with S4C, to which he has acted as a consultant since leaving TSMS in 1996.
It seems likely that because of Contract Rights Renewal, ITV has realised that it would be better off using its leverage for its own wholly owned channels rather than for any third-party contracts. S4C isn't part of the plan so it has, perhaps in desperation, tried to find alternative arrangements.
With Hallmark and Emap currently examining their contracts with Sky Media, the third-party sales arena has now gone into a state of flux.
With the multichannel TV explosion in the mid-90s, the trend was for the established media groups such as Granada, Carlton or Sky Media to represent them.
Indeed, the appointment of one of these players could add millions to a channel's share price. When the late lamented five detractor Adam Faith launched The Money Channel in 1999, he signed up Granada to represent airtime sales. Some £80 million was added to the share price overnight.
TV historians might remember that the channel was a complete failure and soon folded.
So what chance does Lench have of making a success of S4C and other channels that he may win the contract for?
Independent sales teams have to be better than their counterparts at the large sales houses, like Sky Media, where airtime is bundled in with other channels.
"It's great for a media owner to have a dedicated sales team as they know the product better and are therefore more passionate about selling it," Bijan White, the broadcast director at Manning Gottlieb OMD, argues.
Perhaps then, Lench will be able to convince advertisers to take the Principality more seriously and encourage more local advertisers to advertise on television.
However, there is a counter argument that he will struggle to get on any client or agency radar, because he is hardly selling the most compelling proposition.
White says: "If you are relatively small, being in a big organisation such as ITV Sales or Sky Media is a comfort blanket and you are more likely to get access to see agencies and clients."
This lack of scale, combined with a lack of leverage, will be one of the main problems that Lench is going to encounter.
John de Napoli, the managing director of the independent TV sales house Digital Media Sales, knows how difficult getting in to see agencies can be. His privately owned sales house represents a ragbag of channels, none of which can be described as a "must have" on any buyer's schedule.
"It's more difficult being independent - it's a proper sales job and you apply different skills," de Napoli confesses.
Mike Parker, the head of client and strategic sales at Channel 4, says that Lench's existing relationships with broadcast directors might help him in his efforts.
"The strength with Mike Lench is that he's got a fantastic relationship with most senior agency personnel and has done a good job as a consultant for S4C," he argues.
That may be true, but no broadcast director is likely to bother spending time thinking about what share to give to channels of S4C's size. Such decisions are likely to be left to the most junior members of the TV department -and Lench's contacts aren't so good in this arena.
It seems that Lench has got quite a challenge ahead of him if he is to make a success of his venture.
All Sky channels (including Sky music channels); National Geographic;
Adventure One; The History Channel; The Biography Channel; Hallmark
Channel; Emap music channels; Discovery (all except Discovery Kids);
MUTV; Chelsea TV
Digital Media Sales
The Horror Channel; Reality TV; Travel Channel; Motors TV; Game Network;
Overload; NASN; Channel U; Rapture; Classic FM TV; Performance; Teletext
Holidays; M Channel
UKTV channels; LivingTV; Trouble; Bravo; Challenge; Ftn; Extreme Sports