Hi Farmgirl,
Firstly, although at risk of sounding all cliche, Don't give up!! I know it's an avalanche of applications, rejections, frustration and resentment towards the whole scenario, but as already mentioned, there'll be that call which will be someone wanting to take you and your partner on!
Secondly, for the interest of full and rounded knowledge, then yes, you are right, there is a 'undercurrent' of prejudices here in the UK for when it comes to Age of an applicant also race, gender and lately, origins of a person too. It's highly irritating and I absolutely hate it all - My background was in Financial IT and this sector is notorious for not attracting enough women. This was usual to read about in industry publications but thankfully, each of the three American companies I worked for, there was a great mix of male/female employees and from what I could tell, zero discrimination. I was also blessed with colleagues from all over the world so those companies got the blend right in my opinion. Other sectors, perhaps it's more prevalent for the negatives to still exist which makes me irritated firstly with a mild dose of anger too as I know there's many many fantastic very suitable people looking for those jobs - like yourself.
Other factors include where in the UK you are geographically, and the sector of industry you are in and your specific skillset and experience etc.
On top of all that, the UK has recently gone all 'anti immigrant' and 'anti immigration' with the ugly head of more outright/direct racism appearing. Associated with that is the whole outside of EU immigration thing which many UK people who want rid/complain about 'foreigners' keep going on and on about loudly and publicly, which again doesn't help you both at all.
I hope and implore you to keep looking and not to lose heart and here's to hoping you'll soon be posting to say you've both found something !
Cheers, DtM! West London & Sough UK!